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Book._^_.__i^I2 

Copght'N". 

COPYRIGHT DEPOSO: 



IRVING'S 

Catechism of Botany. 



WITH AN APPENDIX 

ON 

THE FORMATION OF AN HERBARIUM. 




Rewritten by 

JAMES HANSEN, O. S. B., St. John's University, 
COLLEGEVILLE. MINN. 



Adapted to the use of Schools in the United States. 



JOHN MURPHY COMPANY, 



PUBLISHERS: 



BALTIMORE, MD.! 
200 W. LOMBARD STREET. 



NEW YORK: 
70 FIFTH AVENUE. 



UBRARY of ; 


CONGRESS! 


fwc Copies 


^ectMVtMi 


AUQ 22 


8905 


aopyngni tiwry 
COPY 6. 






Copyright 1905 by 
John Murphy Company 



TABLE OF CONTENTS. 



Page 

Chapter I. Introduction 3 

Chapter II. Biology 4 

Chapter III. General Morphology .... 8 

Chapter IV. The Plant Body 12 . 

Chapter V. Leaves - 18 

Chapter .VI. The Root . . . . . . .26 

Chapter VII. Flowers 28 

Chapter VIII. The Fruit 34 

Chapter IX. The Seed . . . . . . 37 

Chapter X. Tissues 38 

Chapter XL The Plant Cell 42 

Chapter XII. Reproduction 45 

Chapter XIII. Development ...... 47 

Chapter XIV. Dicotyledons 50" 

Chapter XV. Monocotyledons 55 

Chapter XVL Gymnosperms .57 

• Chapter XVII. Pteridophytes 58" 

Chapter XVIII. Bryophytes 62 

Chapter XIX. Thallophytes ..... 6Q 

Chapter XX. Physiology 69 

Chapter XXI. Special Physiology of Movement . 73 

Chapter XXIL Function of Tissues . . , 75 

Chapter XXIIL Distribution of Plants. .... 76 

Chapter XXI V. Uses of Plants 81 

Chapter XXV. Historical Botany 82 

Chapter XX VL Origin of Plants 85 

Appendix 89 



PREFACE. 



'T'HE Publishers of Irving's Catechisms, being aware that the 
treatment of Botany as contained in the said Catechism of 
Botany had grown considerably antiquated, requested me to revise 
it. In compliance with this request, I have entirely rewritten 
the Catechism with the exception of the Appendix. 

It has been my aim to make the Catechism of Botany as con- 
cise, but also as comprehensive as possible. It is to be used only 
with the aid of a teacher, that will explain and enlarge the 
answers given. 

Thus it is hoped, that the young boys and girls, who study it, 
may learn from it, what questions to ask about plants and get 
an idea of the answers, which the science of Botany is at present 
in a position to give. 



St. John's University, 
Collegevillef Minn.y July^ 1905. 



CHAPTER I. 



INTRODUCTION. 

How pleasing: the task to trace a Heavenly Power, 
In each sweet form, that decks the blooming flower. 
And climb the heights of yonder starry road, 
And rise through nature, up to nature's God. 

Q. 1. What is botany? 

A. Botany is the science of plants. 

Q. 2. How may botany be divided? 

A. Botany may be divided into (1) morphological 
botany; (2) physiological botany; (3) ecological botany; 
(4) economic botany (5) palaeontological botany. 

Q. 3. Of what does morphological botany treat? 

A. Morphological botany or plant morphology treats 
of the organs, tissues, development and classification 
of plants. 

Q. 4. Of what does physiological botany treat? 

A. Physiological botany or plant physiology treats 
of the vital functions of plants. 

Q. 5. Of what does ecological botany treat? 

A. Ecological botany treats of plants in their re- 
lations to one another and to their surroundings. 

Q. 6, Of what does economic botony treat? 

A. Economic botany treats of plants in their re- 
lation to man. 

Q. 7. Of what does palaeontological botany treat? 

A. Palaeontological botany treats of fossil plants. 



BIOLOGY. 



CHAPTER 11. 



BIOLOGY. 



Q. 8. What is Biology? 

A. Biology is the science of life, or rather, of living 
beings. 

Q. 9. How is it divided? 

A. It is divided into zoology, the science of animals, 
and botany, the science of plants. 

Q. 10. Why is biology divided thus? 

A. Because the subject matter of biology, namely 
living beings, are by nature separated into two grand 
groups, called respectively, the animal kingdom, and 
the vegetable kingdom. 

Q. 11. Therefore what is the subject matter of bot- 
any? 

A. The subject matter of botany is the vegetable 
kingdom which comprises all plants. 

Q. 12. What is a plant? 

A. A plant is a living being, with a material organ- 
ization, belonging to the vegetable kingdom. 

Note. — The above definition is given as a matter of convenience. 
The term ''living being'' in contradistinction to lifeless matter; 
the term ''with material organization" in contradistinction to 
spirit; ' 'belonging to the vegetable kingdom'* to distinguish the plant 
from the animal, and to show that the distinction between plant and 
animal life must be taken from the whole kingdom rather than from 



BIOLOGY. 



any one individual or group of individuals. There are other defin- 
itions of plant, e, g. A plant is a non-sentient organism where 
•^organism'' stands for * 'living being, with material organization.'' 
Another definition : A plant is a living being with material organi- 
zation, having vegetative life. These definitions are philosophically 
and theoretically quite correct, but practically not a bit better than 
the one given, since they also throw the question back upon the 
other question, viz: *'How is vegetable life distinguished from 
sentient life? L e. How does plant life differ from animal life? 
The distinction between these two is theoretically quite simple, 
sentient life involving ' 'consciousness, ' ' while vegetable life does not. 
But the difficulty of distinguishing between ' 'consciousness and 
' 'non-consciousness " is no less and no greater in the crucial cases than 
the difficulty of distinguishing between animal and plant life.— 
Scientists have been unable so far to establish an absolute and at 
the same time easily applicable criterion. It is generally admitted 
that the element of consciousness is necessary and sufficient to estab- 
lish the animal nature of a material living being; it is therefore an 
absolute and final criterion. But on account of the difficulty of its 
application in doubtful cases, other more easily applicable criteria 
have been established, none of which, however is absolute. The 
principal ones of these will be given in the next question. 

Q. 13. How are plants distinguished from animals? 

A. Plants may be distinguished from animals (1) 
in structure (2) nutrition (3) products (4) in habits. 

Q. 14 How do plants differ from animals in struct- 
ure? 

A. Plants ordinarily have cell-walls of cellulose, 
while animals have not. Exceptions: (1) slime-moulds, 
diatoms among plants; Tunicates have cellulose in 
mantles. (2) plants have no sense organs, no locomotive 
organs, while animals have them. Exceptions: unicel- 
lular flagellate plants and animals; apparently also the 
hairs on each half of the leaf of the Venus fly trap 
(Dionaea muscipula), etc. 



BIOLOGY. 



Q. 15. How do plants differ from animals in nutri- 
tion? 

A. Generally speaking, plants can subsist on mineral 
food alone, whilst animals cannot. Except: Exceptions 
among plants are the whole class of Fungi, all parasitic 
plants properly so-called, and partially also the insec- 
tivorous plants. 

Q. 16. How do plants differ from animals as regards 
products? 

A. Plants produce starch, sugar and proteids from 
mineral substances and set free oxygen during pho- 
tosynthesis, but this applies only to plants with chloro- 
phyl, while it is claimed that some infusoria produce 
starch. 

Q. 17. How do plants differ from animals in habits? 

A. Plants, as a rule, are stationary, animals mobile; 
Exceptions: lower algae, as desmids, diatoms, also 
bacteria and the spermatozoids of most cryptogams, 
while among animals, the corals, sponges, etc., are in 
their adult stage quite stationary. 

Q. 18. Which are the principal organisms of which 
it is doubtful whether they are plants or animals? 

A. The principal ones are the slime-moulds, which 
by botanists are called myxomycetes i. e,, slime- 
moulds, but by zoologists they are called mycetozoa, 1 e. 
fungus animals; besides these many of the ciliated and 
flagellated, unicellar organisms are claimed by both 
botanists and zoologists. 

Q. 19. What are the grand divisions of the vegetable 
kingdom? 

A. The two grand groups or divisions of the vege- 



BIOLOGY. 



table kingdom are: (1) Flowering Plants, called also 
Phaenogams or Phanerogams and non-flowering 
plants or Cryptogams. 

Following is a synopsis of the classification of the 
vegetable kingdom from Engler and Prantl's. 
''Die Naturliechen Planzenfamilien'' II Teil l.abt. p. 1. 



I DIVISION. 

Mycetozoa — They are also 
called; in the same work, 
Myxomycetes, or Myxothal- 
lophytes. 

1st Class: Acrasiei. 

2nd Class: Myxogasteres. 

3rd Class: Phytomyxini. 

English: Slime moulds, e. g. 
* *Flower-of-tan. ' ' 



II DIVISION. 
Thallophytes. 

SUB-DIVISIONS. 

1st. Schizoph^i:es. 

2nd. Algae. 

3rd. Fungi; including Lich- 
ens, Seaweeds, Pondscum, Bact- 
eria, Mushroom.s, Mildew, 
Molds, Rust, Smut, etc. 



Ill DIVISION. 
Embryophyta zoidiogama, 
formerly called Archegoniatae. 



1st. 
2nd. 



SUB-DIVISIONS. 

Bryophyta. 
Pteridophyta. 



CLASSES OF BRYOPH. 

1st. Hepaticae. 
2nd. Musci foliosi. 

CLASSES OF PTERIDOPHYTA. 

1st. Filicinae. 

2nd. Equisetinae. 

3rd. Sphenophyllinae. 

4th. Lycopodinae. 



IV DIVISION. 

Embryophyta siphonogama, 
formerly called also: Phanero- 



gams, 


Anthophyta, Sperm 


phyta. 






SUB-DIVISIONS. 


1st. 


Gymnospermae. 


2nd. 


Angiospermae. 


CLASSES OF GYMNOSPERMAE 


1st. 


Cycadinae. 


2nd. 


Cordaitinae. 


3rd. 


Coniferinae. 


4th. 


Gnetales. 


CLASSES OF ANGIOSPERMAE. 


1st. 


Monocotyledoneae. 


2nd. 


Dicotyledoneae. 



GENERAL MORPHOLOGY. 



CHAPTER III. 



GENERAL MORPHOLOGY. 

Q. 20. What is plant morphology? 

A. Plant morphology is the study of the resem- 
blances and differences of outer form and internal 
structure of individual plants and their several parts, 
without regard to function. 

Q. 21. What is the method of morphology? 

A. The method of morphology is one of comparison; 
at least principally, since its main task is to trace the 
homologies existing in the vegetable kingdom. 

Q. 22. What is meant by homology? 

A. By homology, in botany, is meant similarity or 
identity of origin and structure. And two parts, of 
the same or of different plants, which have homology, 
are said to be the homologous, and the one is said to 
be the homologue of the other. 

Q. 23. From what other terms must we carefully 
distinguish these? 

A. We must carefully distinguish, between homol- 
ogy and analogy, homologous and analogous, homol- 
ogue and analogue. 

Q. 24. What is analogy? 

A. Analogy, in botany, is similarity or identity of 



GENERAL MORPHOLOGY. 



function in two different parts, without regard to 
structure; and parts which have analogy are said to 
be analogous and also the one is called the analogue of 
the other. 

Q. 25. Give examples of homologues aud analogues. 

A. The green foliage leaves and the coloured floral 
leaves of the rose are homologues of each other, but 
not analogues; also the stem of the rose and the potato 
tuber are homologues, both being stems, but they are 
not analogues, having different functions.; — the 
branches of myrsiphylum and true leaves are analo- 
gues of each other. 

Q. 26. How far does the morphology of plant 
extend? 

A. The morphology of a plant, to be complete, must 
extend over the whole life-history of the plant. 

Q. 27. What is meant by the Hfe-history of a 
plant? 

A. By life-history of a plant is meant an account of 
all the different successive stages, through which the 
plant may pass: that is, the tracing of the plant from 
one particular stage, taken as the starting point, 
through all the different forms which it assumes 
in the course of its development, back to the stage at 
which the start was made. 

Q. 28. What is the most important fact to be consid- 
ered in connection with the life-history of plants. 

A. The most important fact to be considered in 
connection with the life-history of plants is the almost 



10 GENERAL MORPHOLOGY. 

universal occurrence in them of polymorphism. 

Q. 29. What is polymorphism? 

A. Polymorphism of a plant is its power to assume 
two or more essentially different forms of individual 
existence. 

Q. 30. How many different forms does a plant in 
general, pass through? 

A. A plant, in general, passes through two forms 
of individual existence, and hence, ordinarily it is 
dimorphic. 

Note — Exceptions are found among algae and fungi, some 
having only one form, others having more than two forms, 
under which they appear. These will be considered under the 
special morphology of these plants. 

Q. 31. How are the two forms of dimorphic plants 
distinguished? 

A. The two forms of a dimorphic plant, are also 
designated stages or phases of the plant; one of them 
is asexual and is called the sporophyte, the other is 
sexual and is called the gametophyte. 

Q. 32. Define sporophyte and gametophyte? 

A. A sporophyte is that phase of a plant which pro- 
duces only spores in contradistinction to gametes, 
which are produced by the gametophyte of the same 
plant, and are the reason why it is called gametophyte. 

Q. 33. Define spores and gametes. 

A. Spores and gametes agree in this, that both are 
single reproductive cells given off by the parent plant; 
but they differ essentially in this, that every single 



GENERAL MORPHOLOGY. 11 

spore is by its nature capable of giving rise to a new- 
phase of the plant, but that the gametes are not capa- 
ble of doing this; the latter must unite in pairs, i. 6., 
two gametes must coalesce completely so as to 
form but one cell, which is capable of giving rise to a 
new phase of the plant. 

Q. 34. What are these two ways of reproduction, 
called? 

A. Reproduction by spores is called asexual repro- 
duction, and reproduction by means of gametes is 
called sexual reproduction; and since these ways of, 
reproduction, as a rule, regularly alternate with each 
other, they are together known as alternation of gen- 
erations. 

Q. 35. Why is the reproduction by means of 
gametes called sexual reproduction? 

A. It is called sexual reproduction, because it 
resembles or rather is essentially the same as sexual 
reproduction in the animal world. 

Q. 36. What are two principal ways of sexual 
reproduction occurring in plants? 

A. The two ways are; (1) the gametes which unite 
are essentially alike or morphologically indisguishable 
and in this case the process is called conjugation and 
the resulting product is called the zygospore; (2) the 
gametes are unlike, and in this case the process is 
called fertilization and the product is called oospore. 

Q. 37. Why must we distinguish carefully between 
sporophyte and gametophyte? 

A. Because morphology requires that only corres- 



12 THE PLANT BODY. 



ponding parts be compared with one another in order 
to discover the homologies existing in different plants. 
Obviously, therefore, sporophyte must be compared 
with sporophyte, gametophyte with gametophyte. 
And since that, which is ordinarily called the ^^plant," 
may be either the sporophyte, as, for instance, in all 
flowering plants and ferns, or the gametophyte, as, 
for instance, in mosses and many lower plants, 
it is clear that the beginner in botany must early have 
his attention drawn to this important fact. 



CHAPTER IV. 



THE PLANT BODY. 

Q. 38. Of what does a plant's body consist? 
A. A plant's body consists of one or more cells. 

Q. 39. What is a plant cell? 

A. A plant cell is the unit of plant life and struct- 
ure; it is essentially composed of nucleated protoplasm 
and its products; the latter are of great variety, the 
commonest one being the cellwall, which the proto- 
plasm secretes; and it is from the appearance of this 
•cellwall, that the unitof plant life has received its name. 

Q. 40. What is protoplasm? 

A. Protoplasm is the physical basis of animal and 
plant life; i. e. animal and plant life is not found out- 
side of protoplasm. 



THE PLANT BODY. 



13 



Q. 41. Upon what does the shape and form of the 
plant's body depend? 

A. The form of the plant's body depends upon the 
formative activity of the plant's protoplasm. 




Fig. 1. 
PLANT-CELLS IN DIFFERENT STAGES. 
A-young" cells with very thin walls and densely filled with protoplasm; (x 300;) 
B-same kind of cells but older; cell- walls have become thicker, and the protoplasm 
has become vacuolated (300 dia.;) C-cell still older, protoplasm forms a layer on cell- 
wall, while the vacuoles have united to form one large central vacuole; the nucleus in 
protoplasm near cell- walls (100 dia.;) Z>-cell of about same age as C, but differing in 
having the nucleus in central mass of protoplasm, which is connected with the pari- 
etal protoplasm by a number of strands. A and C are frona the young ovary of 
Symphoricarpus racemosus; C and D from the fruit of the same plant, iiZ-cell-wall; 
P-protoplasm; i<!-nucleus; iTX'-nucleolus; S-vacuole. 

Q. 42. How many fundamentally different forms of 
the plant body are there? 

A. There are only two; (1) thallus; (2) the plant's 
body is differentiated into stem and root. 



14 THE PLANT BODY. 



Q. 43. What is a thallus? 

A. A thallus is a form of plant body, which is either 
not segmented at all, or segmented into similar parts 
only. 

Note— These two forms of the plant body afford a criterion 
for dividing the whole vegetable kingdom into two Grand 
Divisions : Thallophytes, i. e., plants whose body is a thallus, in- 
cluding all plants from the lowest unicellar forms up to, but 
excluding the mosses ; cormophytes, including all plants from the 
mosses upwards. 

Q. 44. What is meant by branching? 

A. In morphology, by branching is meant division 
or segmentation into morphologically similar parts or 
segments; while by its opposite, differentiation, is 
meant division or segmentation into dissimilar parts. 

Note— Since the thallophytes divide only into similar parts, 
namely branches, they need not be considered in the following 
questions, which refer only to the differentiated segments of 
cormophytes. 

Q. 45. What are the typical parts, into which a 
cormophyte is divided? 

A. The typical parts into which a cormophyte is 
divided, are root, stem and leaf. 

Q. 46. What distinction must be drawn with regard 
to the segmentation of a cormophyte? 

A. We must distinguish between primary and 
secondary and higher orders of division in the cormo- 
phyte. 



THE PLANT BODY. 15 

Q. 47. What is the primary division in a cormophyte? 
A. The primary division in a cormophyte is its 
differentiation into stem and root. 

Q. 48. What are the secondary divisions? 
A. The secondary divisions are the leaves and 
branches of the stem, and the secondary roots. 

Q. 49. What are the divisions of higher order? 
A. Divisions of a higher order are those which arise 
from those of secondary origin. 

Q. 50. What are the principal forms of stems? 

A. The principal forms of stems are; (1) culm, or 
haulm, (2) trunk, vine, caudex, or (3) scape and (4) 
bulb, corm, rhizome or tuber, stolon or runner. 

Q. 51. What is a node? 

A. A node is that point of a stem where one or 
more leaves originate. 

Q. 52. What is an internode? 
A. An internode is the part of a stem between two 
successive nodes. 

Q. 53. Define culm or haulm. 

A. A culm is a form of stem with elongated inter- 
nodes and a jointed appearance at the nodes, e. g. 
grasses, sedges, etc. 

Q. 54. Define a scape. 

A. A leafless stem or part of a stem rising from a 
subterranean part of the plant and bearing only 
flowers, e. g., dandelion. 



16 THE PLANT BODY. 



Q. 55. What is a bulb? 

A. A bulb is a form of stem with very short inter- 
nodes and fleshy leaves, resembling a bud, e. g,, onion, 
narcissus, etc. 

Q. 56. What is a corm? 

A. The swollen fleshy base of a stem, differing 
from the bulb in being solid, e, g., jack-in-the-pulpit, 
cyclamen, etc. 

Q. 57. What is a rhizome? 

A. A creeping subterranean stem, usually bearing 
scale-like leaves and roots at the nodes and becoming 
erect at the apex, e. g., Solomon's seal, water lily, etc. 

Q. 58. What is a tuber? 

A. A thickened, subterranean branch or part of a 
stem, e, g., potatoes, etc. 

Q. 59. What is a stolon or runner? 
A. A basal branch of the stem disposed to root where 
it touches ground; e. g., runner of strawberry, etc. 

Q. 60. What is a trunk? 

A. A large, solid form of stem as found in trees. 

Q. 61. What is a vine? 

A. A vine is an elongated, slender, trailing or 
twining form of stem; e. g,, grape, Virginia creeper, 
etc. 

Q. 62. What is a caudex? 

A. A caudex is that form of stem which is found in 
perennial herbs, usually only that part which is per- 
sistent above ground. 



THE PLANT BODY. 



17 



Q. 63. What is the typical arrangement of 
branches on the stem? 

A. Branches spring only from the axils of leaves; 
hence, their arrangement on the stem is necessarily 
the same as that of leaves. 




Fig. 2. 
Various f:>rms ofstemi: A-Tiib3rous; B-bulboa^,; C-roDtst">cko:^ rhizome; D-runner 
or stolon of strawberry; ^'-creeping- stem of Ground Ivy, (Nepeta Glechoma) the ii- 
ternodes are twistel in order to bring the leaves in one plane. Fi^'ure A: s stems; 
kn leaf bu 1; k tuber; k list year's tuber from which the stem grow 5; w roots. B : k 
stem; z szile leaves; ssjaie; 6 buds; Z foliage leaves; t<; ro its. C: n s^ale-leaves; 
a stem; Z foliaTe leaves. D: s stolon; n scale-leaves; 6 bad. E: s stem; /foliage 
leaves; a twisted internode; w root. 



18 LEAVES. 



CHAPTER V. 



LEAVES. 



Q. 64. What is a leaf? 

A. A leaf is a primary lateral out-growth of the 
stem. 

Q. 65. Of what parts does a typical leaf consist? 
A. A typical leaf consists of (1) base or foot, (2) 
petiole or stalk, (3) blade or lamina. 

Q. 66. How may leaves differ? 

A. Leaves may differ from each other (1) by the 
presence or absence of the petiole or blade, (2) by 
divisions of either petiole or blade; (3) in venation; 
(4) in outline of blade; (5) in appendages to any of 
their parts. 

Q. 67. Name and describe the chief kinds of leaves 
with regard to these differences. 

I. A leaf having a petiole is called stalked or petio- 
late, while a leaf without petiole is called sessile; a 
leaf which has no proper blade may be; (1) acicular or 
needle-shaped as in pines, or; (2), tendril-like as in 
some vetches; or, (3), cylindrical as in the onion; or 
(4), prismatic as in the stonecrop, etc. 

n. With regard to presence of divisions or their 
absence: a leaf without divisions of stalk or blade, is 



LEAVES. 



19 



called a simple leaf, while leaves having completely 
divided leaf -blades only, or, divided leaf -blades and 
also divided petioles are called compound. Compound 
leaves are either pinnately, or palmately compound 
according as the separate divisions of the leaf -blade, 
called leaflets, are arranged on the sides of an elong- 
ated axis, as for instance, the pinnately compound 
leaf of the sumac; or when the leaflets all appear to 
arise from one point as the palmately compound 
leaf of clover. When the leaflets of the first division 
of a compound leaf are themselves similarly divided, 
the leaf is said to be twice pinnately compound or pal- 
mately compound; these divisions may extend still 
further, so that the leaf may be three times or four 
times compound; e. g., the leaf of the meadow-rue is 
thrice ternately compound. These higher divisions 
however, are often simply called 
decompound. 

III. The venation of a leaf may be 
either reticulate or parallel, pinnate 
or palmate. A leaf is said to be reticu- 
late or net- veined when its veins appear 
to form a net work; but it is parallel 
veined, when the veins appear to run 
parallel to each other. It is pinnate 
veined, when the secondary veins 
arise from a distinct axial vein, termed 
,_ midrib, and palmate- veined when the 



^ V 




Fig. 3. -Netted ven- 
ation of leaf of Willow yelus aHse from the insertion of the 

(salix caprea); m mid- 
rib; n lateral secondary petlOle. 

I^L:. (nTt!l:.f"^ IV. The blades of leaves may differ 



20 



PLANTS. 



in shape, in margin, in apex and base. The 
general shape of the leaf blade may be linear, elhp- 





FiG. 5. — Pinnate venation of 
young- fern leaf, the veins do not 
anastomose; m midrib; ss second- 
ary lateral veins; n smaller lateral 
veins. 



Fig. 4.— Parallel venation 
of grass leaf; veins anas- 
tomosing along marg-in at 
a, a, a, a, a; v veinlet. (x4) 



tical, oval, cordate, lanceolate, peltate, etc. The margin 
or border of the blade may be entire, lobed, cleft, 
dentate, serrate, laciniate, divided, etc. The apex of 
the leaf blade may be acute, emarginate, obtuse, 
mucronate, cuspidate, etc. The base may be acute, 
obtuse, cordate, clasping, auriculate, perfoliate, 
connate, etc. 

V. Among the appendages of the leaf the most 
important are the stipules, which are outgrowths from 
the base or foot of the petiole; they may be foliaceous 



PLANTS. 



21 



membranous, spiny, ocreate, etc. Other appendages or 
Dutgrowths from the leaf are hair, or spines, or scales. 




Fig. Q.— Various forms of leaves : A palmate lobed leaf of Geranium, p petiole; 
Palmate compound leaf of clover, p petiole, p' petiolule, / leaflet. C pinnate, dis- 
sected leaf of shepherd's purse (capsella bursa pastoris) m midrib. D Pinnate, 
compound leaf of Hippocrepis comosa, r midrib or phyllopodium, p' petiolule, f ' leaf- 
let, i terminal leaflet. E Pinnate, compound leaf of Pistacia Lentiscus without 
be rrninal leaflet, r midrib or axis, a wing of axis, /leaflet. F Pinnate compound leaf 
iisting-uished from B because petiolules p' do not rise from one point f leaflet, s 
mucro, spiny projection of midrib. G leaf of the orange must be considered com- 
pound on account of joint, a between leaf and petiole; c wing of petiole. H twice- 
pinnate compound leaf of Acacia, p petiole or principal axis, r' secondary axis /" 
leaflets. 

Q. 68. How are leaves modified or transformed? 
A. Leaves are modified in accordance with their 
function. 



22 



PLANTS. 



Q. 69. Mention some of the principal modifications 
or transformations. 

A. Some of the principal modifications of leaves are, 
floral or perianth leaves, stamens, carpels, spines, 
tendrils, pitchers, scales and bracts. 

Note — The floral leaves and bracts will be considered under the 
flower. Specially transformed leaves also occur, as for instance, in 
onion bulb or cabbage heads for storage of starch. 




Fig. l.—A auriculate clasping leaf of Thlaspi perfoliatum. B perfoliate leaf of 
Bupieurum rotundifolium. C Connate perfoliate leaves of Honeysuckle (Lonicera 
Craprif olium. ) 

Q. 70. What are tendrils? 

A. Tendrils are elongated, thread-like modifications 
of branches or leaves adapted to twine around suitable 
objects and to serve the plant which produces them as 
a means of mechanical support. 

Q. 71. What are pitchers or pitcher-leaves? 

A. Pitchers, such as those of Saracenia purpuria or 



PLANTS. 



23 



Nepenthes, are leaves transformed into insect traps. 
The same may be said of the leaves of the Venus fly- 
trap and of Sundew. 




Fig. 8. — Base of leaf of grass, (Poatrivialis) v sheath, -i ligule, Z blade, astern. B 
willow leaf, (salix caprea) a stem, s stipules, p petiole, /blade, k bud, Cleaf of Pea 
(Pisuna arvense) a stem, s stipules, r axis, /leaflet, r/ tendrils- transformed leaflets. 



Q. 72. What are scales? 

A. Scales, such as are found on buds or underground 
stems are transformed or rudimentary leaves. 

Q. 73. What are bracts? 

A. Bracts are leaves modified with regard to or by 
reason of the flower, but not included among true floral 
leaves. 

Q. 74. How are leaves arranged on the stem? 

A. Leaves are outgrowths from the nodes of the 



24 PLANTS. 



stems; and they occur either singly or in groups at 
each node. When they occur singly their arrrangement 
is called alternate, when in groups it is called verticil- 
late or whorled. The simplest group consists of two 
at a node; this is called opposite arrangement, all 
groups greater than this are whorls. 

Q. 75. How are leaves arranged vertically on the 
stem? 

A. The vertical arrangement of successive leaves 
always is a spiral, whether the leaves are whorled or 
alternate; moreover, they are arranged in a definite 
number of vertical lines parallel to the axis of their 
stem, which are called ranks or orthostichies. 

Q. 76. What is the relation of the spirals and the 
ranks to each other? 

A. The relation of the spirals and ranks of the 
leaves can be very briefly expressed by the series, (f), 
h h h h T3 , 2 T, ih ih it will be noticed that the num- 
erators of the different fractions are formed by adding 
the two preceding numerators, the same rule holding 
also for the denominators. Now as to the meaning of 
the fractions: the numerator expresses the number of 
turns the spiral makes around the stem in passing 
from any leaf in a definite rank or orthostichy along 
the successive leaves, back to the next leaf in the same 
rank, above or below that from which the start was 
made. The denominator expresses the number of 
leaves successively passed through in making the 
turn or turns. 



PLANTS. 



25 




Fig. ^.—Diagram of lee f 
arrangement of alternate 
leaves: The leaves are 
arranged or inserted in 
eight vertical rows called 
ranks or orthostichies, 
marked in the figure by 
Roman numbers I, II, etc. ; 
the leaves are marked ac- 
cording to their succession 
1, 2, 3, etc., and are con- 
nected by a spiral line, 
which is called the genetic; 
it makes three turns be- 
tween two successive leaves 
of same rank and passes 
through eight leaves: hence 
the divergence is ^/s. 



Q. 77. Give examples of some of 
the above arrangements of leaves. 

A. The leaf arrangement or 
phyllotaxy of the elm and hornbean 
is expressed by the fraction J; also 
that of all grasses; that of all sedges 
and of the alder is J, the f arrange- 
ment is the most common occurring 
in the cherry, poplar and many 
other trees and shrubs; § is 
found in the orange, theholly aud 
common plantain; both § and -^ 
occur in the acicular leaves of firs 
and spruces; 9^ and 



2 1 



34 



occur m 



pine-cones and heads of compositae. 

Note — There are leaves which form ex- 
ceptions to the above rules, e. g., the alga. 
Polys 'phonia has a J leaf arrangement. 

Q. 78. How are the two sides or 
surfaces of a leaf distinguished? 

A. The side which faces the 
stem or upwards is called the ven- 
tral side, while the other which 
faces away from the stem or down- 
wards is called the dorsal side of 
the leaf. 



26 THE ROOT. 



CHAPTER VI. 



THE ROOT. 

Q. 79. What is the plant root? 

A. When the plant body is differentiated into dis- 
similar parts, one group of the parts forms the stem or 
ascending axis with its members while the other forms 
the root or descending axis with its members. 

Q. 80. What are the principal kinds of roots? 
A. The principal kinds of roots are the primary smd 
secondary roots. 

Q. 81. What is a primary root? 

A. The primary root is the first root of a seedling. 

Q. 82. What are secondary roots? 
A. Secondary roots are branches of the primary 
root. 
Q. 83. What other kinds of roots may be met with? 
A. Adventitious or aerial roots. 

Q. 84. What are adventitious roots? 

A. Adventitious roots are secondary roots arising 
from the stem or any of its parts different from lower 
end where the primary root arises; adventitious mem- 
bers in general are such as have an abnormal origin. 

Q. 85. What are aerial roots? 

A Aerial roots are secondary roots arising from a 



THE ROOT. 



27 



part of the stem above ground and serving as hold- 
fasts for it; e. g., the aerial roots of ivy, poison ivy. 

Q. 86. How are roots properly so-called, modified? 

A. Underground roots may be modified for the 
purpose of storing starch etc., in them, when they are 
thick and fleshy, and are called taproots; e. g., beet, 
turnip, etc., or they may be adapted to attack the roots 
of other plants for the purpose of taking sap from 
them, when they are called parasitic; e. g., gerardia, 
bastard toadflax, etc. 




Fig. 10.— Germination of seed of dicotyledon, the bean (Vicia faba,) on left. A. 
Seed split into halves, one half removed; s seed-coat, to hypocotyl, kn epicotyl or 
plumule, c seed-leaf or cotyledon. B. Bean germinating; he hypocotyl, h primary 
root, ivs root tip, s seed-coat, st petiole, of seed leaf, i and k epicotyl, n bud. On 
righ, young Maple seedling; c seed leaves, kn epicotyl, he hypocotyl, w primary root, 
h root hairs. 



28 FLOWERS. 



Q. 87. What are the principal forms of roots? 

A. Roots are either fibrous, i. e,, thread-like, or tub- 
erous, e, (/., dahlia, or nodulose, 1 6., swollen at the 
nodes. 

Q. 88. What appendages do roots ordinarily de- 
velope? 

A. Roots ordinarily do not develope leaves and 
never reproductive organs; but they do ordinarily 
develope hair-like appendages called root-hairs. 



CHAPTER VII. 



FLOWERS. 

Q. 89. What is a flower? 

A. A flower is a portion of the stem or its branches in 
the higher plants, modified for the purpose of produc- 
ing spores, i. 6., reproductive cells. 

Q. 90. What is a complete flower? 
A. A complete flower is one that has pistils, stamens, 
corolla and calix. 

Q. 91. What is a pistil? 

A. A pistil is a modified leaf, called a sporophyll, 
i, 6., a leaf bearing spores; it is made up of three parts 
when complete: (1) ovary, (2) style, (3) stigma. 

Q. 92. What is the ovary? 

A. The ovary is a simple or compound chamber 
formed by the walls of the sporophyll and containing 



FLOWERS. 



29 



the ovules or rudimentary seeds. The specialized 
part of the ovarian chamber on which the ovules are 
born is the placenta; the ovules are morphologically 
sporangia, bearing each a single spore which for its 
size is called the macrospore, it is also known as egg- 
cell or embryo-sac. 







iV- 



— "-it i 





Fig. 11. — Flowers of Ranunculaceae; s peduncle, k sepals, e petals, a stamens 
/pistil. A, Pasqueflower (Anemone Pulsatilla) cut through middle of axis, /i bracts, 
t torus or receptacle B. Pistils of Crowfoot, a one stamen left on receptacle, n 
the dots marking the points of insertion of the other stamens which were removed. 
C. Complete flower from below. D. Flower of Hellebore. E. Flower of Monks- 
hood, h bractlets, /c' transformed sepal or hood, c transfoi-med petals. 

Q. 93. What is the style? 

A. The style is an elongation of the apex of the 
ovary bearing on its upper end a glandular surface 
called the stigma. 



30 FLOWERS. 



Q. 94. What place in the flower does the pistil 
occupy? 

A. The pistil occupies the innermost place in the 
flower. 

Q. 95. What is a stamen? 

A. A stamen is a modified leaf, called also a micro- 
sporophyll, because it bears microspores which are 
generally known as pollen. The stamen generally con- 
sists of two parts: a thread-like stalk called filament 
bearing the pollen-sacs or pouches, which are known 
as anthers. 

Q. 96. What is the corolla? 

A. The essential organs of the flower; namely, 
pistils and stamens are generally surrounded by two 
sets or circles of modified leaves; the inner set or 
circle is called the corolla, the outer the calix and both 
together are called perianth. The leaves of each set 
being either separate or grown together; the separate 
leaves of the inner set or corolla, are called petals 
those of the outer set or calix are called sepals. 

Q. 97. How may flowers differ among each other? 

A. Flowers differ among each other,: (1) by the 
presence or absence of some of their parts; (2) in the 
number of the respective parts; (3) in position and 
cohesion, or adhesion of the parts; (4) in various shapes 
of the parts. 

Thus— I: the corolla may be absent, and then the 
flower is apetalous, or both the corolla and the calix, 
then the flower is naked or achlamydeous; v/hen only 



FLOWERS. 31 



one of the two is absent, it is always the corolla. 
When the stamens are wanting, the flower is pistillate 
and conversely, when the pistils are wanting, the 
flower is staminate, and when both are wanting it is 
neutral. 

11. The difference in the number of the respective 
parts gives rise to the different plans of the flower. 
The principal kinds are the plan of three, i. e., the 
different floral parts as sepals, petals, stamens and 
pistils are three in number, or a multiple of three; 
this plan is typical of the monocotyledons; the plan of 
four or five, when the parts number four or five or 
multiples of these numbers; both these plans are typi- 
cal of the dicotyledons. 




Fig. 12. On left flower of stonecrop; parts all separated from each other; on 
right, flower of gooseberry, showing- cohesion and adhesion of the sepals, petals, 
stamens and pistils; k calyx, c corolla (petals), st stamen, b disk, g style. 

III. The principal differences of flowers, arising 
from the relative position or insertion of its parts, are 
those that are founded on the relation of the position 
of the pistil and of the other parts. ( See flgure 12.) 

By cohesion is meant the growing together of parts 
of the same set, while by adhesion is meant the grow- 



32 FLOWERS. 



ing together of parts of different sets. The former 
gives rise to compound pistils, monadelphous stamens 
mono or sym-petalous corolla, etc., while the 
latter gives rise to apparent differences of position. 

When all the parts of a set are similar to each other 
they are called regular; when this is true in all the 
respective sets, the whole flower is regular. If one or 
more of the sets have one or more dissimilar parts the 
whole flower is irregular. The commonest irregular- 
ties are transformation of the corolla or calix or parts 
thereof into a nectary, i. e,, a gland producing a sweet, 
liquid, popularly called honey, but botanically known 
as nectar. 

Q. 98. What is meant by inflorescence? 
A. Inflorescence signifies the arrangement of flow- 
ers on the stem. 

Q. 99. What is the arrangement of flowers? 
A. Since flowers are the homologues of branches, 
their arrangement is the same as that of branches, i, e., 
axillary or ternimal, or both. 

Q. 100. What is axillary inflorescence? 

A. Axillary inflorescence obtains when the flowers 
arise from the axils of leaves and is also called inde- 
terminate or acropetal, and is further known as the 
racemose type. 

Q. 101. What constitutes a terminal inflorescence? 

A. An infl.orescence is terminal when all its separate 
flowers terminate branches, and hence it is called 
determinate and is further known as the cymose type. 



FLOWERS. 



33 



Q. 102. Name some of the principal inflorescences 
of the racemose type. 

A. Raceme, corymb, umbel, spike, head, spadix, 
catkin or ament, and panicle. 




Fig. 13. — Diagrams of racemose inflorescences : A. Spike. jB. Compound raceme. 
C. Compound umbel; i involucre, i involucel, d ray, dl secondary ray. D. Head, 
i involucre, p bract, 6 flower. 




Fig. 14 —Diagrams of cymose inflorescences : The numbers indicate the order of 
succession of the flowers; No. 1 being first to open. No, 2 second, etc, A and B 
scorpioid, C dichasial, D helicoid cyme. 



34 THE FRUIT. 



Q. 103. Name the principal cymose inflorescences. 
A. Cyme, fascicle and cymule. 

Q. 104. Instead of a definition mention a common 
or a well known example of each. 

A. Example of raceme e, g,, forget-me-not, pepper- 
grass, of corymb, the hawthorn genus; umbel, the whole 
parsley family; spike, the common plantain; head, 
clover, dandelion, aster, spadix, jack-in-the-pulpit, calla 
lily, catkin, or ament, flowers of willow, poplar, hazel; 
panicle, oats, buckeye. Examples of cyme, elder, wild 
cranberry, fascicle, day flower, spiderwort; cymule, 
chickweed, pearlwort. 



CHAPTER VIII. 



THE FRUIT. 

Q. 105. What is meant botanically by fruit? 

A. The fruit is, in a strict sense, the ripened pistil. 
But often, after fertilization, parts adjacent to the 
pistil develope in a special way and in combination 
with the pistil and thus become parts or appendages 
of the fruit. 

Q. 106. What is the seed? 

A. The seed is the ripened ovule. 

Q. 107. What does the seed contain? 

A. The seed contains the young plant or embryo 
with or without nourishment for it, in the shape of 
starch, oil, etc. 



THE FRUIT. 35 



Q. 108. What is therefore the relation of seed, em- 
bryo, and fruit? 

A. The fruit contains a seed or seeds, the seeds 
contain the embryos; the fruit serves as a protection 
to the seed and very often as a means for the dispersal 
of the latter; the seeds serve as a protection to the 
embryo and generally also supply nourishment for 
its germination. 

Q. 109. How may fruits be classified? 
A. Fruits may be classified into simple and com- 
pound; true and spurious; dry and fleshy. 

Q. 110. Define these. 

A. A simple fruit is a single ripened pistil; a com- 
pound fruit consists of several ripened pistils. A true 
fruit consists of the ripened pistils only; a spurious 
fruit consists of the ripened pistil along with other 
parts intimately united to it. A dry fruit is one having 
no flesh or pulp; a fleshy fruit is one that is more or 
less juicy throughout. 

Q. 111. Mention some of the fleshy fruits. 

A. The principal fleshy fruits are the berry, the 
drupe, the pepo or gourd-fruit. The pome or apple 
is also fleshy but not a true fruit, since the fleshy part 
is the greatly developed calix; a berry is fleshy 
throughout as gooseberry, cranberry, grape, tomato; 
but not the strawberry, the fleshy part being the 
greatly increased receptacle or summit of the floral 
axis. 

Q. 112. What are the two principal kinds of dry 
fruits? 



36 



THE FRUIT. 



A. The dry fruits are distinguished into dehiscent 
and indehiscent fruits. A dehiscent fruit is one which 
when ripe opens to let out the seeds; an indehiscent 
fruit is one that remains closed. 




Fig. 15. — Dry dehiscent fruit. A. Pod or legrnne of pea; r dorsal suture, h ventral 
suture, c calyx remnants, s seeds. B. Septicidal capsule of Colchicum autumnale; 
/separate carpel. C. Silique as found in mustard family, k valves, s septum or par- 
tition, s seed. D. Fruit of the Poppy (Papaver somniferum) n stigma, j pores, a 
valves covering pores. E. Pyxis of Henbane; d lid, s seeds, w partition. 

Q. 113. Mention the principal dehiscent fruits. 
A. The dehiscent fruits are compound capsules, 
such as the fruit of the blueflag, follicle or simple 



THE SEED. 37 



pod splitting along one side only; legume splitting 
along both sides, e. g,, beans and peas; the silique the 
two sides of which split away from a central partition; 
the pyxis, a pod the top of which comes off as the lid 
from a dish, and the cone, the fruit peculiar to pines 
and most gymnosperms. 

Q. 114. Mention the principal indehiscent fruits. 

A. They are the akene, as the fruit of buttercup, 
crowfoot, sunflower, dandelion, etc., the caryopsis or 
grain, as corn, wheat, etc., the samara or winged fruit, 
e. g.y maple, ash, elm, boxelder, etc. 



CHAPTER IX. 



THE SEED. 

Q. 115. What is the most important part of the 
seed? 

A. The most important part of the seed is the em- 
bryo or young plant contained in it. 

Q. 116. Describe the embryo? 

A. The embryo is generally so far developed in the 
seed, that the following parts can be made out: (1) 
cotyledon or seed leaf, (2) radicle, caulicle or hypocotyl 
which is the descending axis of the embryo and devel- 
opes the primary root; (3) the plumule or epicotyl, the 
ascending axis, the stem, bearing scales or rudimen- 
tary leaves. 

Q. 117. How many cotyledons or seed leaves has 

the embryo? 



38 TISSUES. 



A. The embryo has two cotyledons in the dicoty- 
ledonous plants, one in the monocotyledons, and 
several in most gymnosperms. 

Q. 118. How is the nourishment for the embryo 
usually stored in the seed? 

A. The nourishment for the embryo, is usually 
stored in the form of starch or oil or proteid matter in 
one of the following ways: (1) in the greatly enlarged, 
thick cotyledons, as in beans, acorns and most dicoty 
ledons; (2) it surrounds the embryo, i. e. the embryo 
is embedded in the nourishment, which in this case is 
called endosperm, as in wheat, corn and most mono- 
coty ledons. 



CHAPTER X. 



TISSUES. 



Q. 119. What is meant by tissue in botany? 

A. Multicellular plants consist of many similar or 
dissimilar cells; layers or systems of similar cells are 
called tissues. 

Q. 120. How may different kinds of tissues be dis- 
tinguished? 

A. In two ways, (1) with regard to their power of 
growth and division or multiplication; (2) with regard 
to form of cellwall, contents and their chemical con- 
stituents. 

Q. 121. How many kinds do we distinguish accord- 
ing to the first of these ways? 



TISSUES. 



39 



A. Respecting capacity for division or growth, two 
kinds of tissues are to be distinguished: (1) meristem 
or embryonic tissue still capable of growing; (2) adult 
or permanent tissue incapable of further growth. 

Q. 122. How many kinds of tissue are to be distin- 
guished with regard to form and constituents? 

A. The following kinds are distinguished by form 
of cell wall or constituents; (1) parenchyma, (2) prosen- 
chyma, (3) collenchyma, (4) sclerenchyma, (5) cuticu- 
larized parenchyma, (6) tracheal or vascular, (7) sieve 
tissue (8) glandular tissue. 

Q. 123. How are these different tissues to be 
grouped? 

A. They are to be 
grouped into (1) such as 
are derived from paren- 
chyma, (2) such as are 
derived from prosen- 
chyma (3) such as are 
specialized cells from 
their very origin. 

Q. 124. What is paren- 
chyma? 

A. Parenchyma or 
fundamental tissue con- 
sists of thin walled cells 
which are more or less 
isodiametric, 1 e., whose 
diameter is approxi- 
mately constant, no matter in what plane it is taken. 




Fig. 16. Cross-section of petiole Hellebore 
(20 dia. ) ; e epidermis, g parenchyma, /fibro- 
vascular bundle, x xylem or wood, c bast, 
b sclrenchyma. 



40 



TISSUES. 



Q. 125. What is prosenchyma? 

A. Prosenchyma is a tissue composed of elongated 
thinwalled cells, which are, as it were, spliced together 
at the ends; in this way they differ from parenchyma 
whose constituent cells meet more or less at right 
angles. 




Fig. 17.— Upper figure A a cross-section, the lower B a longitudinal section of fibro- 
vascular bundle of sunflower; m parenchyma, x wood, c cambium p bast, ^ -ortex, 
s and s' spiral ducts, t and t' pitted ducts, h wood-fibre, sb sieve tube, b bast fibres, 
e endodermis (150 diameters). 



Q. 126. What is collenchyma? 



TISSUES. 41 



A. Collenchyma is parenchymatous tissue, the cell- 
walls being thickened at adjoining corners. The 
substance constituting this thickening is capable of 
becoming glue or gelatine and hence the name. 

Q. 127. What is sclerenchyma? 
A. Sclerenchyma is prosenchyma with very much 
thickened walls, as occurring especially in bast fibres. 

Q. 129. What is tracheal or vascular tissue ? 

A. Tracheal or vascular tissue consists generally of 
prosenchyma, with lignified and variously thickned 
and bordered or perforated walls ; it is distinguished 
into two principal kinds : 1. Tracheids, closed 
tracheal cells, the wall between the successive 
cells persists. 2. Tracheae, the walls between 
the successive cells are absorbed and the cells are 
usually also of a larger diameter; from their ap- 
pearance and function they are also called ducts or 
vessels. 

Q. 130. What is sieve tissue ? 

A. Sieve tissue consists of elongated cells or tubes 
communicating through specialized openings, called 
from their appearance, sieve-plates. 

Q. 131. What is glandular tissue ? 

A. Glandular tissue consists of cells specialized for 
the purpose of secreting or excreting certain sub- 
stances, as for instance, aromatic oil, nectar, latex or 
milk, etc. 



42 THE PLANT CELL. 



CHAPTER XL 



THE PLANT CELL. 

Q. 132. How does the typical plant cell differ from 
the typical animal cell ? 

A. The typical plant cell differs from the typical 
animal cell, in this, that it surrounds itself by a cell- 
wall which at first is always composed of the 
chemical substance cellulose, while the animal cell is 
lined by a protoplasmic membrane. 

Note.— There are exceptions in both kindgoms, nevertheless this 
difference in the separate cells is responsible for most of the 
difference of appearance and general behavior between plants and 
animals. 

Q. 133. How do cells come into existence ? 

A. So far as is known, both plant and animal 
cells arise only by division of pre-existing cells. 
Cell-division is always preceded by the division of the 
nucleus. 

Q. 134. In how many ways does nuclear-division 
take place ? 

A. In two ways : 1. Direct or amitotic. 2. In- 
direct or mitotic. 

Q. 135. What is direct nuclear-division ? 
A. Direct nuclear-division or amitosis takes place in 
the following manner: the nucleus of the parent 



THE PLANT CELL. 



43 



cell constricts, without apparent change, in the 
configuration of the chromatin ; the constriction in 
the middle of the nucleus advances until finally it is 
separated into halves. 




1^ 





Fig 18. (540 dia ) Direct division of nucles: afresh, Rafter staining- with acetic 
methyl-green in cells of old internodes of common spiderwort. 

Q. 136. What is indirect nuclear-division ? 

A. Indirect nuclear-division, called also mitosis or 
karyokinesis, is so designated on account of a series 
of complicated changes, which accompany it. The 
nucleus appears transformed into a bipolar spindle 
of arched fibres, in the equatorial plane of which the 
chromatin gathers in the shape of a thread or spirem; 
this thread breaks into a definite number of parts 
called daughter-chromosomes, which split lengthwise 
and move along the spindle fibres to the opposite 



44 



THE PLANT CELL. 



spindle-poles; there they fuse into a new nucleus, 
and then a cell-wall is secreted at the equatorial 
plate of the spindle, thus separating the two new cells. 




Fig. 19. Indirect cell-division or mitosis or karyokinesis, in pollen mother-cell of 
Fritillaria persica (800 dia.) a chromatin contracted in nuclear cavity, on its upper 
surface lies the nucleolus; 6 polar view of c bi-polar spindle, chromatin gathered in 
equatorial plate of spindle, d polar view, e equatorial plate or the chromosomes com- 
posing: it split into halves, /chromosomes sliding along- the spindle fibres to opposite 
poles of spindle, g formation of daughter nucles at poles, the spindal still visible, h 
spirem stage of daughter nuclei, i spindal formation, k equatorial plate stage, I halving 
of chromosomoes, ?n formation of grand-daughter nuclei. 



REPRODUCTION. 45 

Q. 137. What is the relative importance and 
frequency of occurrence of these two modes of 
nuclear-division ? 

A. Mitosis or indirect nuclear-division is, by far, the 
most common mode of nuclear- formation, the direct 
mode being extremely rare ; moreover, as the latter 
occurs only in old tissues, it is now generally con- 
sidered as a last feeble effort of the cell to grow, 
though only mitosis is followed by cell-division ? 



CHAPTER XIL 



REPRODUCTION, 

Q. 138. How many different modes of reproduction 
occur among plants ? 

A. The following : 1. Sexual reproduction. 2. 
Asexual reproduction. The latter is again of two 
kinds, namely Rejuvenescence and vegetative 
reproduction. 

Q. 139. What is vegetative reproduction ? 

A. Vegetative reproduction, which should rather 
be called propagation, consists in this that a part or 
member of the parent plant-body is separated from it, 
and then develops as an independent plant. 

Q. 140. What are the principal ways in which 
vegetative reproduction or propagation may lake 
place ? 

A. They are the following: 1. By specialized 
branches or parts of stem as bulbs, bulbils, rhizomes, 



46 REPRODUCTION. 



tubers, runners, stolons, which naturally propagate 
the plant ; also but more rarely by specialized roots, 
as, for instance, those of the Jerusalem artichoke. 
Dahlia, etc. 2. Any node of the stem, branch or even 
leaf may, theoretically at least, be made to propagate 
the plant, and as is well known this is the florist's and 
gardener's favorite method, especially when they 
wish to preserve the peculiar qualities, which any 
particular plant has. 2. Propagation by means of 
gemmae, which occurs especially in plants that have 
no true stem, therefore, from the Byrophytes down- 
ward. Since the gemmae vary from highly 
specialized bodies, multicellular in structure, down to 
nuciellular gemmae, this method gradually leads 
over to rejuvesence or spore-reproduction. 

Q. 141. What is meant by rejuvescence ? 

A. By rejuvescence is meant a peculiar change 
which the protoplasm of a cell may under definite 
circumstances undergo. This peculiar change of the 
protoplasm of a cell make take place in such a 
manner that the whole protoplasm of one cell contracts 
to form one or more spores, i. 6., cells capable of 
giving rise directly to another individual plant like 
the one from which the spores were derived ; or it 
may give rise to cells which must each unite to 
other homologous cells in order to give rise to a 
new individual. The first of these methods is 
called spore reproduction, the second sexual re- 
production ; so that it appears that rejuvescence is a 
phenomenon that appears in spore formation and in 



DEVELOPMENT. 47 



gamete-formation only, and therefore is a special 
phenomenon of reproduction. 

Q. 142. What is the principal difference between 
spore reproduction and sexual reproduction ? 

A. The principal difference consists in this that 
spores are able to reproduce the plant each for 
itself, while the sexual reproduction requires that two 
morphologically similar spore-cells, called in this 
connection gametes, must unite and fuse in order to 
produce a new individual. This latter fact, i. e,, the 
necessity of union of two gametes seems to be due to 
the reduction of the number of chromosomes to one- 
half the number that is found in the nucleus of the 
sporophyte. 



CHAPTER XIII. 



DEVELOPMENT. 

Q. 143. What is growth ? 

A. Growth is change of form with or without in- 
crease of mass. It is brought about by protoplasm 
that is still in its embryonic condition. When pro- 
toplasm reaches the adult condition it ceases to grow. 

Q. 144. In what directions may growth take place ? 

A. Growth may take place in one direction only, 
in which case the result is a thread of greater or 
less length ; or growth may occur in two directions, 
when the result is a fiat expanded body known as a 
thallus, or finally, growth occurs in three dimensions 



48 DEVELOPMENT. 



and the result is a solid, at first globular, but on ac- 
count of unequal growth, it soon becomes more or 
less cylindrical. 

Q. 145. What is normally associated with growth ? 
A. Cell-division is normally associated with growth. 

Q. 146. Is growth localized or does it take place 
uniformly throughout the growing part ! 

A. In many of the lower algae and in the beginning 
of the development of the embryo of higher plants 
growth is quite uniform ; but it becomes localized as 
the plant body increases, i, e., a portion of the pro- 
toplasm passes into the adult condition and ceases 
to grow, while the other portion remains active and 
this difference in the activity of the protoplasm is 
responsible for the inequality of growth and, hence 
for the form and shape of the plant body. 

Q. 147. What is a growing point ? 

A. A growing point is a definite region of a tissue 
where cell-division still takes place ; it is called 
growing "point" because ordinarily it is restricted to 
a small area, very often to a single cell. 

Q. 148. How are growing points distinguished ? 
A. Growing points are distinguished, according to 
situation, into apical, marginal and intercalary. 

Q. 149. Define these? 

A. The apical growing point is situated at the 
apex of the stem or root, or, in fact, of any axis ; the 
intercalary growing point is situated between the 
base and apex, while the marginal is situated on the 



DEVELOPMENT. 



49 



margin ; often the whole margin of a thalloid plant 
is embryonic, i. e., capable of growth. 





^. 



c: 



Fig. 20.— Growing points: A. Terminal (Stypoeaulou scoparium; 30dia). B. 
Intercalary (Desmarestia ligulata, 60 dia.) C. Terminal (Chaetopteris plumosa, 
40 dia.) branches arising from lateral divison of apical cell. 



Q. 150. What 
there ? 



other growing point or tissue is 



A. The apical, intercalary or marginal growing 
points effect growth in length and also give rise to 
the normal lateral members ; but many perennial 
plants, especially all perennial dicotyledons,grow in 
thickness each year ; this is effected by growing or 
meristematic tissue surrounding the stem or root in 
the shape of a hollow cylinder, and is generally known 
as cambium or meristem. 



50 DICOTYLEDONS. 



CHAPTER XIV. 



DICOTYLEDONS. 

Q. 151. What are dicotyledons ? 

A. Dicotyledons are the highest class of flowering 
plants or rather of the whole vegetable kingdom; 
they are the dominant plants of the present geological 
era ; they receive their name from the fact that 
the embryo of these plants, as contained in the seed, 
has two seed leaves or cotyledons. 

Q, 152. Do the dicotyledons exhibit alternation of 
generation ? 

A. The dicotyledons normally have alternation of 
generations. 

Q. 153. What is the relative development of the 
two phases ? 

A. The two phases are very unequally developed, 
that is to say, the gametophyte stage is very in- 
conspicuous, while the sporophyte is highly 
developed, and is represented by that, which we call, 
^^the plant'' or ^'the tree.'' 

Q. 154. What stages of development are comprised 
in the life-history of a dicotyledon ? 

A, All the stages from the germination of the ripe 
seed to the production of ripe seed. 

Q. 155. Into how many kinds of plants are the 



DICOTYLEDONS. 51 



dicotyledons divided with regard to the duration of 
their life-history ? 

A. With regard to the duration of their life-history, 
dicotyledons are divided into three kinds, viz., an- 
nual, bi-ennial and perennial plants. 

Q. 156. What is an annual dicotyledon ? 
A. It is one that completes its life history in the 
course of one season, e, g,, bean, pea, etc. 

Q. 157. What is a bi-ennial dicotyledon ? 

A. A bi-ennial dicotyledon is one that completes its 
life-history only in the course of two seasons, e. g,, 
the beet, turnip, carrot, cabbage, etc. In the first 
season these plants germinate from the seeds and 
grow rapidly, but do not produce flowers or seeds; 
instead of it they store up nourishment in the fleshy 
roots, as for instance, the beet, carrot, or in the leaves, 
as the cabbage. The second season they produce 
flowers and seeds and then die a natural death. 

Q. 158. What is a perennial dicotyledon ? 

A. A perennial dicotyledon is one whose life does 
not cease with the first production of flowers and 
seed, but which continues for an indefinite number of 
seasons to produce flowers and seed, as for instance, 
all dicotyledonous trees and shrubs. 

Q. 159. What are the principal stages of develop- 
ment in an annual dicotyledon ? 

A. They are the f ollov/ing : 1. The embryo stage of 
the sporophyte. 2. The seedling or young growing 
sporophyte. 3. The fully developed sporophyte with 



52 DICOTYLEDONS. 



mature spores in its flowers. 4. The male and female 
gametophyte. 5. Fertilization and development of 
seed. 

Q. 160. What is the typical form of the embryo of 
dicotyledons ? 

A. The typical form of the dicotyledonous embryo 
has the following parts while still in the seed : 1. 
The descending axis, radicle or hypotyl. 2. Two 
cotyledons or seed leaves. 3. Plumule or epicotyl, 
the ascending axis. 

Q. 161. Is there any differentiation of tissues in 
this stage of the sporophyte? 

A. As a general rule there is very little if any 
differentiation into tissues, depending how^ever some- 
what upon the variable degree of development which 
the embryo of different plants attains in the seed ; if 
any differentiation obtains, it consists of meris- 
stematic parenchyma and prosenchyma. 

Q. 162. By what changes does the embryo pass 
into the seedling stage ? 

A. Under the proper conditions of temperature, 
moisture and air the embryo in the seed begins to 
grow ; this is called germination. First the radicle or 
hypocotyl elongates and grows dow^n into the 
substratum ; when it has secured a firm foothold, and 
not before, the plumule or hypocotyl elongates in its 
ascending growth ; next the cotyledons may or may 
not be lifted above ground and begin to function, as 
leaves assisting the first small leaves formed on the 
epicotyl. Simple and unimportant as this last fact, 



DICOTYLEDONS. 



53 



namely, the elevation and transformation of the 
cotyledons into functioning leaves may appear at 
first sight, it involves, nevertheless, a reversion of 
the general tendency of growth of the radicle 
or hypocotyl ; for the elevation of the cotyledons 
cannot be due to anything else than upward 
elongation of the hypocotyl, and yet the general 
tendency of growth of the hypocotyl is away from the 
light and towards moisture or nourishment and 
yielding to the pull of gravity. In spite of all, this 
difference of behavior does occur in closely related 
plants, e. g., the ordinary garden bean and pea, the 
bean always elevates or at least attempts to elevate 
its cotyledons and transform them into green leaves, 
while the pea never makes an effort in this line. 

Q. 163. What other changes take place during the 
change of the plant from the embryo to the seedling ? 

A. The hypocotyl 



produces the primary , 
and generally also 
secondary roots, the 
epicotyl produces 
leaves and branches, 
while the tissues 
undergo complete 
differentiation. 

Q. 164. What dif- 
erentiation of tissue 
is found in the seed- 
ling stem of dicoty- 
ledons ? 




Fig. 21. Cross-section of young stem of Aristo, 
lochia Sipho; c parenchyma cl collenchyma, sk 
sclerenchyma belonging- to pericycle pc, ifc inter- 
fascicular cambium, fv fibrovascular bundles, fc 
fascicular cambium, vl wood, m pith parenchyma, 
p youngs bast, ch sieve-tissue and bast. 



54 DICOTYLEDONS. 



A. The seedling stem-tissue is the following : The 
outer layer of cells is the epidermis ; the next, the 
cortex (parenchyma), then the fibro-vacular bundles 
arranged radially with connecting or intrafascicular 
cambium. 

Q. 165. What differentiation of tissue is found in 
the root ? 

A. The same differentiation of tissue obtains in the 
roots as in the stem, only it is not so pronounced. 

Q. 166. What new development does the fully 
developed sporophyte exhibit ? 

A. The only new development which the fully 
developed sporophyte shows is the reproductive 
organs or flowers. 

Q. 167. What are flowers morphologically ? 
A. Morphologically flowers are leaves bearing 
reproductive cells called spores. 

Q. 168. How many kinds of spores are there in 
dicotyledons ? 

A. There are always two kinds of spores in the 
dicotyledons, viz., macrospores and microspores. 

Q. 169. What are these spores ? 
A. The macrospore is the embryo sack of the 
ovule, the microspore is the pollengrain. 

Q. 170. What is the gametophyte of dicotyledons? 

A. The gametophyte of dicotyledons is of two 
kinds, viz., the female and the male. The female 
gametophyte is the embryo sack with its development 
up to fertilization ; the male gametophyte is the 
germinating pollengrain up to fertilization. 



DICOTYLEDONS. 55 

Q. 171. What is fertilization ? 

A. Fertilization is the union and fusion of the egg 
nucleus with the generative nucleus of the pollentube. 
From the oo-spore thus produced the embryo of the 
sporophyte is developed. 

Note— In the seed ordinarily the embryo passes a resting stage, 
more or less prolonged. 



CHAPTER XV. 



MONCOTYLEDONS. 

Q. 172. What is a monocotyledon ? 

A. A monocotyledon is an angiosperm whose 
embryo has only one cotyledon or seed leaf. 

Q. 173. How does the germination of monoco- 
tyledons differ from that of dicotyledons ? 

A. Principally in this, that the single cotyledon is 
never elevated above ground, though it may persist 
for a long time. The other development is essentially 
the same. 

Q. 174. How does the seedling of monocotyledons 
differ from that of a dicotyledon ? 

A. It differs essentially only in the distribution of 
the tissues. 

Q. In what does this difference consist ? 

A. This difference consists in the irregular distri- 
bution of the fibro-vascular bundles and in the 
absence of true meristematic tissue or cambium. In 
dicotyledons the fibro-vascular bundles are arranged 
radially, i. 6., star-like, while in the monocotyledons 



56 DICOTYLEDONS. 



there is no definite order beyond this, that they are 
more numerous toward the periphery. 

Q. 176. How does the adult monocotyledon differ 
from the adult dicotyledon ? 

A. The adult monocotyledon differs from adult 
dicotyledon in following points : 1. A cross-section 
of the stem of the dicotyledon shows the fibro- 
vascular bundles arranged radially, i. e., in rings, but 
the monocotyledon does not. 2. The leaves of the 
dicotyledons are typically netted-veined, while the 
leaves of the monocotyledon are paralled-veined. 3. 
The flower of the dicotyledon is generally on the 
plan of five or two or their mutiples, while that of 
monocotyledons " is on the plan of three and its 
multiples. 

Q. 177. What other difference is there between 
dicotyledons and monocotyledons ? 

A. There is another marked difference between 
these two forms in their adaption and manner of 
secondary growth, or growth in thickness. The 
dicotyledons have typically a special tissue to secure 
secondary growth, called cambium, which the mo- 
nocotyledons do not have. The principal reason for 
this is that the monocotyledons, with the exception 
of palms and their relatives, are mostly annual 
plants, while the contrary is the case with dicoty- 
ledons and gymnosperms. 

Q. 178. What plants belong to the monocotyledons? 

A. All grasses, sedges, orchids, lillies, palms, cereals, 
etc. 

Note.— Dicotyledons and monocotyledons together constitute the 
angiosperms, so called because their seed^ are produced in a closed 
vessel. 



GYMNOSPERMS. 57 



CHAPTER XVI. 



GYMNOSPERMS. 

Q. 179. What are gymnosperms ? 

A. Gymnosperms are distinguished from angio- 
sperms in this, that they have their seeds naked., i. e., 
not contained in carpels. 

Q. 180. How does the gymnosperm differ from the 
dicotyledon and monocotyledon? 

A. It differs from these two: 1 In the number of 
cotyledons. 2. In germination. 3. In reproduction. 

Q. 181. How does the gymnosperm differ from the 
angiosperms in number of cotyledons? 

A. In this, that its embryo has more than two, up 
to fifteen cotyledons. 

Q. 182. How does it differ in germination ? 
A. In this, that the whole seed is raised above 
ground where seed coats are cast off. 

Q. 183. How does it differ in reproduction? 

A. In this, that the spores are not contained in a 
closed vessel, but are naked, and hence the name of 
the class. 

Q. 184. In what other respect do they differ from 
angiosperms ? 
A. Principally in this, that they have no true 



58 PTERIDOPHYTES. 



vascular tissue or ducts ; but they agree with 
dicotyledons in secondary growth. Another dif- 
ference is the arrangement of their flower into 
typical clusters called cones. 

Q. 185. What plants belong to this class ? 
A. The conifers, as pines, spruces, firs, cedars, the 
Gnetaceae, cyras, etc. 

Q. 186. What division of the vegetable kingdom do 
the plants so far specialized constitute ? 

A. They constitute the spermaphyta or seed-bear- 
ing plants. 



CHAPTER XVII. 



PTERIDOPHYTES. 

Q. 187. What plants belong to this group ? 

A. To this group belong ferns and related plants, 
that is in descending order : 1. Clubmosses. 2. 
Horsetails and scouring rushes. 3. Ferns. 

Q. 188. In what relation does this group of plants 
stand to the other plant groups ? 

A. It is the highest group of cryptogams, and the 
only one in which true vascular tissue is found, 
hence they are also called the Vascular cryptogams. 
They are the crytogams nearest in form and structure 
to the flowering plants, the spermaphytes. 

Q. 189. Do the Pteridophytes have alternation of 
generations ? 
A. The Pteridophytes show a well-marked alter- 



PTERIDOPHYETS. 59 



nation of generations. That phase of them which is 
known as the ^'plant" is the sporophyte, while the 
inconspicuous gametophyte phase is called the pro- 
thallus or prothallium. 

Q. 190. What is the relation of the plants of this 
group among themselves and to the spermaphytes as 
regards spore-characteristics? 

A. As regards their spores, the Pteridophytes are 
of two kinds, m;e;. : 1. Homosporous, i.e., spores pro- 
duced are all alike. 2. Heterosporous, i. e., spores 
produced are of two kinds, viz.^ large ones, called 
macrospores, and small ones, called microspores. It is 
evident, therefore, that the latter, the heterosporous 
Pteridophytes, lead over to the Spermaphytes, while 
the homosporous forms lead down to the mosses. 

Q. 191. Which plants of this group are hetero- 
sporous ? 

A. The heterosporous plants of this group are: 
1. Selaginellaceae. 2. Isoetaceae or quillworts. 3. 
Hydropterideae, as Salvinia, Azolla, Marsilea, Pilu- 
laria. 

Q. 192. Which are homosporous? 

A. Homosporous are : 1. Lycopodiaceae and Psilo- 
taceae or clubmosses. 2. Equestaceae or horsetails. 
3. Ferns. 

Q. 193. What are the principal stages of develop- 
ment from spore to spore ? 

A. They are: 1. Spore. 2. Prothallium or 
gametophyte. 3. Sporophyte. 

Q. 194. What is the principal difference between 



60 



PTERIDOPHYTES. 



homosporous and heterosporous plants of this group 
as regards the prothallium ? 

A. The principal difference is this : The homo- 
sporous spores generally develop into a prothallium 
which has male and female organs, while the hetero- 
sporous spores develop only male prothallia from the 
microspore and only female prothallia from the 
macrospore. 




Fig. 22.— Development of gametophyte of ostrich fern (Onoclea); A. Spore with- 
out outer cot, B same g-erminatins?, C young- prothallium, r rhizoid. D and E older 
prothallium, a growing- point, F" female prothallium from below, r rhizoids, ar arche- 
gonia (12 dia,), G and H longitudinal section of young archegonia, o egg-, Slower, 
c upper canal cell (150 dia.), I ripe archegonium opening, o qq^, J male prothallium 
(500 dia.) an, antheridia, r rhizoid K, L longitudinal section of young antheridia 
(300 dia.), mripe antheridium (300 dia.), sp spermatozoids (300), A^and O antheridia 
discharging spermatozoids, P ciliated free swimming spermatozoids, v vesicle 
(500 dia.). 



PTERIDOPHYTES. 61 



Q. 195. Describe the gametophyte of these plants ? 

A. The gametophyte consists of a small, flat thallus 
of homogeneous tissue bearing the reproductive 
organs, viz., antheridia and archegonia. 

Q. 196. Describe the sporophyte ? 

A. The sporophyte is generally differentiated into 
stem, leaf and root. In the higher clubmosses the 
stem and leaves are above ground ; in the equis- 
etaceae the stem is partially beneath (rhizome), and 
partially above ground,- as also in the case in the 
ferns. 

Q. 197. What is the appearance of the game- 
tophyte ? 

A. The gametophyte, whether male or female, or 
both, is generally a thalloid body of greater or less 
extent bearing the sexual organs on its lower side. In 
the heterosporous forms the prothallium is formed in 
the spore and projects only slightly from it, and 
produces either one antheridium or one archegonium. 
In the homosporous forms the prothallium is either a 
somewhat tuberous body, as in the clubmosses, or a 
more or less flattened thallus, as in the horsetails and 
ferns, but it becomes free from the spore. 

Q. 198. Describe briefly the development of the 
sporophyte ? 

A. The spermatozoids produced and set free from 
the antheridium at the proper time and condition 
swim towards and enter the archegonium, then one of 
them fuses with the egg-cell, which then secretes 



62 BRYOPHYTES. 



a cell-wall so that no more can enter ; after a period 
of rest this fertilized egg-cell develops directly or 
indirectly into the sporophyte. 

Q. 199. How are these plants classified. 

A. They are classified according to the character 
of the sporophyte, especially according to the way it 
bears the spores. 

Q. 200. How are the spores borne in the plants of 
this group ? 

A. In the Selaginellaceae they are borne in more or 
less distinct cones; in the equisetaceae in distinct 
terminal cones ; and in the ferns they are borne in 
sori or clusters on the dorsal sides of special leaves. 



CHAPTER XVHI. 



BRYOPHYTES. 

Q. 201. What is the next lower group of plants ? 
A. The next lower group of plants includes the 
Mosses or Bryophytes. 

Q. 202. What plants come under this heading ? 
A. Under this heading the liverworts and the true 
mosses are included. 

Q. 203. What distinguishes them from the pre- 
ceding group ? 

A. They differ from the preceding group princi- 
pally in this, that they have no true roots nor true 
vascular tissue. 



BRYOPHYTES. 63 



Q. 204. Do the plants of this group show a distinct 
alternation of generations ? 

A. They do ; and just here is where the greatest 
difference, morphologically, between them and the 
preceding group comes in ; in the foregoing group 
the sporophyte is principally developed, and is, there- 
fore, called "the plant," while in this group the 
gametophyte is principally developed, and is called 
"the plant;' 

Q. 205. Describe the sporophyte of the bryo- 
phytes. 

A. The sporophyte, called also sporogonium or 
sporophore, differs considerably in the two classes of 
plants of this group. In the liverworts it consists of 
a capsule or vessel raised on a stalk called seta ; the 
capsule splits on maturity into a certain number of 
valves. In the true mosses the sporogonium consists 
of a spore-capsule raised, as a rule, on a foot or stock 
called seta ; on maturity the capsule opens generally 
by a lid, or splits irregularly. In both, the sporophyte 
never becomes entirely independent of the game- 
tophyte, but throughout its life draws nourishment 
from it. 

Q. 206. What special arrangement is found in these 
plants for the disposal of spores ? 

A. In the true mosses the mouth of the spore- 
capsule is surrounded by a single or double wreath of 
hygroscopic hair, which open when moist and close 
when dry. In the liverworts, elaters or hygros- 
copic hair are developed among the spores ; they 



64 



BRYOPHYTES. 



curl up when dry and suddenly expand when 
moistened. 

Q. 207. In what other plants are elaters found ? 
A. They are also found in the horsetails where 
they are attached to the spores. 




Fig. 23.— Forms of liverworts: A. Riccia (nat. size). B. Horned liverwort, sp 
sporogania. C. Lunulori? (nat. size), cc gemmae. E. Piece of epidermis showing 
breathing pores in middle of cells. D. Giant liverwort (nat. size) an antherilia. 
F. Common liverwort, x cupules containing gemmae. G. Female receptacle of 
common liverwort (nat. size.). H. Two young gemmae (150 dia). I. Ripegemme. 
J. Cross-section through thallus, s breathing pore (50 dia.). K. Breathing pore 
much enlarged. L. Jungermannia, sp sporogonium. 

Q. 208. How do the gametophytes of the liver- 
worts and mosses compare ? 

A. The gametophyte of the liverworts is a thalloid 
green body except in the Jungermanniaceae. In the 
same mosses the gametophyte is a leafy green shoot. 



BRYOPHYTES. 



65 



Q. 209. Briefly describe the life-history of a 
liverwort ? 

A. The spore, under favorable conditions of 
moisture and temperature, germinates and grows 
into a small, flat body called the prothallium, which in 
the thalloid forms develops directly into the mature 




Fig. 24. — Structure of moss Funaria: A. Young: sporophyte inserted on g-ameto- 
phyte, sp sporophyte. B. Mature sporophyte cal. calyptra, sp capsule. C Capsule 
without calyptra, op lid. -D. Spores; i fresh, ii-iv g-erminating-. E. Teeth from 
mouth of capsule (50 dia.). F. Epidermis of sporophyte with breathing pores or 
stama (150 dia). G. Longitudinal section of spore-capsule, sp spore-mother cells, 
^port G enlarged 300 times, sp spore-mother cells. 

plant, but in the f oliose Jungermanniace, a bud from 
it gives rise to the stem and leaves. The sexual 
organs, namely the female archegones and the male 
antherdia are born on the end of stem or branches 
in f oliose forms, but they are sunk in the tissue of 



66 THALLOPHYTES. 



the thallus in the thalloid Hverworts. Fertilization is 
brought about by the actively swimming anthero- 
zoids, one of which fuses with the egg-cell of the 
archegone. From the fertilized egg the sporophyte 
is developed. 

Q. 210. Describe briefly the life-history of a true 
moss? 

A. The spore and germination gives rise to a 
thread-like, green growth called the protonema. 
From buds on the protonema springs the gametophyte. 
The sexual organs, corresponding entirely with 
those of the liverworts, are situated on the end 
of the stem or lateral branches, and are surrounded 
by a rosette of leaves which gives them the appear- 
ance of small flowers. Fertilization takes place 
in the same way as in the liverworts, and also the 
development of the fertilized egg into the sporophore, 
only the wall of the archegone is generally carried 
upwards as a cap on the spore-capsule ; it is 
called the calyptra. 



CHAPTER XIX. 



THALLOPHYTES. 

Q. 211. What is the next lower group of plants ? 

A. The next lower group of plants is the thal- 
lophytes. In contradistinction to this group all the 
preceding groups together constitute the cormophytes, 
because in them only a true stem is developed, and 



THALLOPHYTES. 67 



this is what the name indicates, viz,, stem-plants ; but 
in the thallophytes no true stem is ever developed, 
but only a thalloid plant-body, and hence their name. 

Q. 212. What plants belong to the thallophytes ? 
A. To the thallophytes belong the plants known as 
Algae and Fungi. 

Q. 213. How are they related to each other? 

A. They differ from each other principally in this, 
that the algae have chlorophyl or leaf -green, while 
the fungi have not ; the algae have mostly a true 
cellular structure, i. e., they are made up of cells, while 
all fungi, except the unicellular ones, have a coeno- 
cytic structure, i, e., they are made up of coenocytes;* 
in most other respects the two groups of plants are 
more or less parallel. 

Q. 214. What are the principal plants belonging to 
the Algae ? 

A. They are : 1. Characeae. 2. Seaweeds. 3. 
Pondscum. 4. Waternets and green slimes. 

Q. 215. Name the principal fungi ? 

A. They are : 1. Toadstools or mushrooms. 2. 
Puff-balls. 3. Rusts and mildews. 4. Moulds. 
5. Bacteria and yeasts and, doubtfully. 6. The 
Myxomycetes or mycetozoa. 

Q. 216. What other plants must be classed with 
these ? 

A. The lichens ; these are very interesting on 
account of being partly fungus and partly alga, which 

*Cocnocyte— nulti-mucleated cell. 



68 THALLOPHYTES. 



have, as it were, formed a partnership for mutual 
benefit. The greater portion of the Hchen-body 
consists of fungus hyphae, embedded among which are 
some of the lower Algae. 

Q. 217. Do the thallophytes exhibit alternation of 
generations ? 

A. A few of them do, but many of them make up 
abundantly for this defect by an unexpectedly com- 
plicated polymorphism, which is very far from benig 
easily traced or understood. 

Q. 218. Which of them have alteration of gene- 
rations ? 

A. Among Algae, Rhodophyceae or Red Algae, and 
in most bright green algae, although the sporophyte 
is extremely rudimentary. Among fungi a sort of 
alternation of generations occurs in the moulds and 
Ascomycetes or sac-fungi. 

Q. 219. What is the stage of plant which is ordi- 
narialy called ^'the plant'' in this group ? 
A. It is the gametophyte. 

Q. 220. What is peculiar about the gametophyte of 
this group of plants ? 

A. The gametophyte of most of the plants of this 
group has the peculiar capacity of producing repro- 
ductive cells, almost or quite indistinguishable from 
spores, except for the fact that they are borne by the 
gametophyte, and hence, to distinguish them from 
true spores, they are called gonidia. 

Q. 221. Under what two principal forms do they 
occur. 



PHYSIOLOGY. 69 



A. 1. As swarmspore or zoogonidia, consisting of 
naked cilated or flagellated cells having no cell-wall 
and capable of swimming in water. 2. Gonidia 
having a cell-wall and incapable of free movement. 

Q. 222. Are the plants of this group of economic 
importance ? 

A. The Algae are of compartively little importance, 
but among fungi some of the most useful as also 
the most hurtful plants are found. Useful are the 
yeasts and ferment producing bacteria ; hurtful and 
correspondingly feared and hated are the disease- 
producing bacteria. Many of the higher fungi are 
considered excellent food for man. 

Q. 223. What is the mode of life of fungi ? 

A. Since fungi are without chlorophyll they are in- 
capable of living on mineral food alone, as green 
plants ; on this account the fungi all told must either 
be parasitic, i. 6., secure their food from a living host, 
or saprophytic, i. 6., secure their food from dead 
animal or vegetable matter. 



CHAPTER XX. 



PHYSIOLOGY. 

Q. 224. How may we define plant physiology ? 

A. We may define it as the study of the vital 
activities of the plant. 

Q. 225. From what must we carefully distinguish 
the vital activities of the plant ? 

A. We must carefully distinguish the vital phe-. 



70 PHYSIOLOGY. 



nomena or activities from merely chemical or merely 
physical phenomena. 

Q. 226. Under what headings may the life activities 
of a plant be classed ? 

A. They may be classed into such as, 1. sub- 
serve the development and maintenance of the 
individual plant; and, 2. Such as subserve the product- 
ion of new individuals like itself, i. e., the maintenance 
of the species. 

Q. 227. What phenomena belong under these 
headings ? 

A. Here belong: 1. The absorption of new material. 
2. Tranformation of this absorbed raw material or 
food into the body substance of the plant. 3. The 
oxidization of certain substances of the plant 
occasioned by the movements or work of the plant. 4. 
The special phenomena of reproduction. 

Q. 228. By what processes does the plant absorb 
new material ? 

A. The absorption of water containing soluble 
substances is accomplished by a process called 
osmosis by physicists ; it consists in the diffusion 
or passage of dissolved substances through a per- 
meable membrane, which in the plant is the cell-wall. 
But the plant absorbs also gases, generally through 
special openings in the outer tissue, which are called 
stomata. 

Q 229. Which parts of the plant absorb water and 
the substances dissolved in it ? 



PHYSIOLOGY. 71 



A. Principally the roots and their analogues, the 
rhizoids, but in many submerged water plants, water 
is also absorbed by the leaves and stems. 

Q. 230. What are the principal substances which 
the plant absorbs along with water and dissolved 
in it? 

A. They are principally various salts of ammonia, 
potassium, calcium, sodium and magnesium for 
plants that have chlorophyl ; parasitic and sapro- 
phytic absorb dissolved organic compounds, as 
peptones^ sugars, etc. 

Q. 231. What are the principal gaseous substances 
absorbed by plants from the air ? 

A. They are carbon dioxide and free oxygen for 
chlorophyl-possessing plants, and oxygen only, or 
oxygen and nitrogen for some of the lower fungi, e. 
g.f soil bacteria. 

Q. 232. Why does the plant absorb just these 
substances ? 

A. Because they contain the food of the plant in 
a suitable form, that is, they contain those chemical 
elements which are indispensable to the plant's 
maintenance of life. 

Q. 233. Which elements are necessary for the 
plant's life. 

A. They are Carbon, Hydrogen, Oxygen, Nitrogen, 
Sulphur, Iron and Potassium; of secondary im- 
portance are Phosphorus, Calcium, Sodium, Mag= 
nesium. Chlorine and Silicon, 



72 PHYSIOLOGY. 



Q. 234. Why are these substances necessary ? 

A. Because of them the living substances and its 
products, namely all other substances found in the 
different parts of plants, are composed. 

Q. 235. What are the principal substances of which 
plants are composed ? 

A. They are : 1. Nitrogenous substances. 2. Non- 
nitrogenous, according to as they contain the 
element nitrogen or not. 

Q. 236. Mention the principal nitrogenous sub- 
stances ? 

A. They are : 1. Protoplasm. 2. Proteids. 3. 
Amides. 4. Alkaloids and some coloring matters. 

Q. 237. Mention the principal non-nitrogenous 
substances? 

A. They are classed : 1. Carbohydrates, namely, 
cellulose and starch and the sugars, glucoses and 
Sucroses. 2. Organic acids, as oxalic, malic, citric, 
tartaric, etc. 3. Glucosides, as amygdalin, myrosin, 
coniferin, salicin, tannin. 4. Fats and fixed oils. 
5. Volatile or essential oils. 

Q. 238. What is the process in general called by 
which the absorbed mineral substances are trans- 
formed into the organic substances ? 

A. The whole process is called by the general name 
metabolism. It consists of two opposite activities, 
namely the splitting up or breaking down of the com- 
plex chemical compounds, and then the combination or 
construction of the simpler elements or compounds 



PHYSIOLOGY 73 



into organic substance. The former series of pro- 
cesses is known by one general name, catabolism, 
the latter by anabolism, and both together constitute 
assimilation. 

Q. 239. What are the conditions necessary for these 
processes to grow ? 

A. They are principally: 1. Supply of food. 2. 
Light. 3. Proper temperature. 

Q, 240. Whence comes the energy necessary for 
the work preformed during these processes ? 

A. From one or both of the following sources? 
1. From sunlight. 2. Chemical energy. 

Q. 241. What process absolutely requires a certain 
amount of light ? 

A. The assimilation of carbon dioxide, which is 
accomplished by chloroplasts only in sufficiently 
intense light. 

Q. 242. What temperature is necessary for these 
processes? 

A. The range of temperature, in which these 
processes may take place, varies widely for different 
plants within the limits, 0° to SO^'C. The best tem- 
perature, i, 6., the most favorable, ranges about from 
25° to 35''C. There are, however, exceptions to both 
statements. 

CHAPTER XXL 



SPECIAL PHYSIOLOGY OF MOVEMENT. 

Q. 243. Why do we consider plants living things ? 

A. Principally because they exhibit movement, 
both automatic or spontaneous, and also induced or 
reflex movements. 



74 PHYSIOLOGY. 



Q. 244. Mention some of the principal movements 
of plants ? 

A. Automatic or spontaneous are : 1. Cir- 
culation or rotation of protoplasm. 2. Nutation of 
growing points. Induced movements : 1. Heliotro- 
pism. 2. Geotropism. 3. Hydrotopism. 4. Chemo- 
tropism. 5. Diurnal or periodic movements. It 
is often very difficult, if not impossible to distinguish 
spontaneous from induced movements, and it may 
perhaps not be wide of the mark to say that the two 
are never completely separated. 

Q. 245. What is Heliotropism ? 

A. Heliotropism is the power or capacity of an 
organ of a plant to turn toward or away from light; 
in the former case it is called positive, in the latter 
negative Heliotropism. 

Q. 246. What is Geotropism? 

A. Geotropism is the capacity of an organ of a 
plant to move with or against the force of gravitation. 
The former is positive, the latter negative geotro- 
pism. 

Q. 247. What is Hydrotropism ? 

A. Hydrotropism is the capacity of an organ to 
turn towards or away from moisture or water. The 
former is positive, the latter negative hydrotropism. 

Q. 248. What is chemotropism ? 

A. Chemotropism is the capacity of an organ to 
turn towards or away from certain chemical sub- 
stances ; the former is positive, the latter negative 
chemotropism. 



FUNCTIONS OF TISSUES. 75 

Q. 249. What is nutation ? 

A. Nutation is the motion of terminal growth- 
points in a plane perpendicular to their growth or 
extension in length ; it is approximately either in 
circles or ellipses. 

Q. 250. What other movements are there in plants? 

A. Special movements in response to definite 
stimuli, as in insectivorous plants like sun- 
dew or the Venus fly trap ; or the drooping of leaves 
and branches in consequence of a jarring, as in 
Mimosa pudica. Also many stamens are sensitive to 
contact, and some fruit capsules, as those of the 
Jewel-weed or Touch-me-not. This quality of the 
plants is called irritability, or rather it is the proof 
of it. Besides, there is the power of spontaneous 
movement in many of the lower plants, as diatoms,* 
desmids, flagellatae, and in the zoospores, gametes 
and spermatozoids of higher plants; and this is one of 
the factors which makes it so difficult to distinguish 
the lower plants from the lower animals. 



CHAPTER XXII. 



FUNCTIONS OF TISSUES. 

Q. 251. What is the function of the epidermis ? 

A. The function of the epidermis is protection of 
the underlying tissues, from mechanical injury and 
especially from too much evaporation. 

Q. 252. What is the function of vascular tissue ? 

A. The vascular tissues are comparable to a pipe 

*It appears that the movement of diatoms is passive, i. e., purely 
mechanical, induced by the emergence of the oxygen gas produced 
by the diatom. 



76 DISTRIBUTION OF PLANTS. 

system for the transfer or movement of liquids in the 
plant. 

Q. 253. What is the function of fibrous tissue ? 
A. The function of fibrous tissue is to give firmness 
and rigidity to the plant body. 

Q. 254. What is the function of sieve tissue ? 
A. The function of sieve tissue is believed to be 
principally the transfer of proteid matter. 

Q. 255. What is the function of glandular tissue ? 
A. The function of glandular tissue is the produc- 
tion and secretion of special products. 

Q. 256. What is the function of meristem ? 
A. The function of meristem or cambial tissue is 
secondary growth. 

Q. 257. What is the function of parenchymatous 
tissue ? 

A. It is the seat of the metabolic processes and also 
of the sensitive phenomena. 



CHAPTER XXIII. 



DISTRIBUTION OF PLANTS. 

Q. 258. How are plants distributed ? 

A. Plants are distributed with regard to region or 
country ; with regard to environment and with regard 
to time. 

The study of plants with regard to their regional 
distribution or occurrence, constitutes geographical 



DISTRIBUTION OF PLANTS. 77 

botany ; the study of plants with regard to environ- 
mental distribution, constitutes ecological botany or 
simply ecology ; the study of plants in regard to dis- 
tribution in time constitutes paleobotany. 

Q. 259. What are all plants naturally growing in a 
country or region collectively called? 

A. They are called collectively the flora of the 
region or country. 

Q. 260. How are plants to be distinguished in re- 
gard to their occurrence in a country ? 

A. Plants native to the country must be distin- 
guished from those that have become naturalized in 
the country within recent time. 

Q. 261. How may the native plants commonly be 
told from the naturalized ones ? 

A. From the mode of their occurrence ; native 
plants occur throughout the region, wherever there is 
a favorable locality for them, while naturalized plants 
are more or less restricted to the localities, where they 
were introduced, as for instance, along railroads, 
harbors or ocean ports and along water courses ; how- 
ever, some weeds spread so rapidly ; that the fact of 
their being naturalized and not native plants can only 
be determined from historical evidence. 

Q. 262. Is there any great difference in range of 
distribution of the various plants ? 

A. There is a wide difference between various plants 
in this regard ; some species being cosmopolitan, i. e. 
of almost universal occurrence, while the flora of 



78 DISTRIBUTION OF PLANTS. 

almost every country contains a number of plants 
peculiar to it. 

Q. 263. How may plants be considered from the 
stand-point of ecology. 

A. In a two- fold way ; 1. Vast areas or zones of 
plant-formations. 2. Local plant societies. 

Q. 264. What are the principal plant formations of 
the first type ? 

A. They are : 1. Arctic tundras. 2. The coniferous 
and deciduous forests and the steppes and prairies of 
the temperate zones. 3. The desert plants of the 
temperate and the tropic zones. 4. The tropical ever- 
green forests. 

Q. 265. To what factors are these plant formations 
due? 

A. They are due to climatic factors, i. e., to tem- 
perature, moisture and winds. 

Q. 266. To what factors are the plant societies of 
the second type, i. e., the smaller local plant formations 
due? 

A. They are due in the first instance to the topo- 
graphy and soil conditions and secondarily to changes 
in these as well as in the struggle for existence of 
the plants themselves. 

Q. 267. How are plants classified in regard to this 
secondary type ? 

A. They may be classified into hydrophytes, meso- 
phytes and xerophytes. 

Q. 268. What are hydrophytes ? 



DISTRIBUTION OF PLANTS. 79 

A. Hydrophytes are such plants as grow only in 
water or at least require abundance of moisture in 
the soil. 

"" Q. 269, What are xerophytes? 

A. Xerophytes are such plants as may get along 
with a little or a minimum of moisture both in the 
soil and in the air. 

Q. 270. What are mesophytes? 

A. Mesophytes are such plants as in their general 
habits and requirements keep the golden middle 
between the two preceding types. 

Q. 271. Where may plants belonging to the three 
types be readily found ? 

A. Generally on lake and river shores, where it is 
possible ordinarily to see the zones of the different 
plant societies merging into each other. 

Q. 272. How are plants distributed in regard to 
time? 

A. It is, in general, admitted that the more highly 
a plant is organized and specialized, the more recent 
it is in regard to its first appearance on the earth. 
The evidence for this is of course taken from geology; 
in a general statement, we may say that, the older 
astrata is in which plants are found, the lower and the 
less specialized are the fossil plants found therein. 

Q. 273. What is the oldest geological age or period 
in which dicotyledons are known? 
A. From the Cretaceous period upwards. 



80 DISTRIBUTION OF PLANTS. 

Q. 274. From what geological period are the mono- 
cotyledons first known ? 
A. From Triassic period. 

Q. 275. In what formation or strata are the Pteri- 
dophyta found for the first time ? 
A. In the Devonian strata. 

Q. 276. In what formation, the Bryophyta ? 
A. Throughout the tertiary period and probably in 
the mesozoic. 

Q. 277. In what formation are Thallophytes first 
encountered ? 

A. In the Silurian period and they thus include the 
oldest known plant fossils. 

Q. 278. What is to be noted about the fossil 
plants of the different geological periods ? 

A. The significant fact that each had its dominant 
plants, i. e., plants which in that particular age at- 
tained their greatest development, both in individuals 
and in numbers. Thus just as flowering plants are the 
dominant plants at the present geological period, so 
formerly Gymnosperms, Pteridophytes and Thallophy- 
tes were the ^'plants'' in their respective ages or 
periods. 



USES OF PLANTS. 81 



CHAPTER XXIV. 



USES OF PLANTS. 

Q. 279. What is the relation of the vegetable to the 
animal kingdom ? 

A. There is an intimate relation between them in 
so far as the latter depends for its food, and hence its 
maintenance directly or indirectly upon plants; but 
the relation is mutual in so far as plants depend, to 
some extent at least, upon the carbon-dioxide which 
animals produce or exhale, for their food. 

Q. 280. What are the principal uses that man 
makes of plants ? 

A. Plants supply directly or indirectly all the vege- 
table food of man and the domestic animals, e. g., all 
the cereals, corn, rye, barley, wheat, etc., fruits, linen 
and cotton, paper, rubber, medicines, oils, liquors, 
wood for fuel and lumber; besides they free the air 
from the poisonous carbon-dioxide and adorn his 
gardens and parks and landscapes; while the higher 
plants are busily engaged in this work, the lower, es- 
pecially fungi and bacteria are acting as scavengers, 
breaking up and decomposing organic substances, thus 
setting free the chemical elements composing them, 
making them available again for the plants; thus play- 
ing as it were the roll of the printer's devil as he 



82 HISTORICAL BOTANY. 

reasserts the type-letters of a setting that has finished 
service. The only trouble about these lower plants is, 
that they are frequently too eager to begin their 
work of destruction, and so become harmful. 

Q. 281. In what ways do plants become harmful to 
man? 

A. Plants are harmful to the farmer, when under 
the name of w^eeds, they crowd out the crop he in- 
tended to raise, or when as parasites they destroy the 
crop, of as pathogenic, i. e., disease-producing bac- 
teria they destroy both animals and man himself. 



CHAPTER XXV. 



HISTORICAL BOTANY. 

Q. 282. When and with whom may the origin of 
the scientific Botany be said to date? 

A. Scientific Botany dates from Aristotle, 384-322, 
B. C, and his school, the Peripatetics. He wrote two 
books on Botany, which were lost. But his pupil and 
successor Theophrastus, wrote a history of plants 
about 300 B. C. Plants were also studied by the 
priests and physicians of the ancients, e. g.^ by Aescu- 
lapius and his followers among the Greeks; also the 
cultivation of grain and fruits naturally led to a cer- 
tain knowledge of plants. Among the Romans, Plinius 
the Elder should be mentioned, for he described several 
hundred plants, most of them being medicinal or 
believed to be so; according to his own words, his 



HISTORICAL BOTANY. 83 



descriptions are compiled from other writers and not 
based on his own studies. 

Q. 283. Who is the next notable author on Botany? 

A. Botany made little or no progress from Pliny's 
time down to Blessed Albert the Great, Bishop of 
Ratisbon, 1193-1280— It was he who restored Aristotle, 
both in philosophy and the natural sciences. He 
wrote six books on plants; they are based on the pre- 
ceding authors and also for a large part on his own 
observations. Descriptive and systematic Botany re- 
ceived a new impulse from Andrew Caesalpinus (1519- 
1603) professor of Botany at the University of Padua. 
The discovery of the microscope enabled botanists to 
study the minute anatomy of plants. The pioneers 
in this line of research were Nehemias Grew (1641- 
1712) secretary of the Philosophical Society of London; 
Marcello Malphigi, professor at Bologna (1628-1694) 
and the father of Microscopy, Anton van Leeuwenhoek 
(1632-1723); Rob. Morison (1620-1683), John Ray (1628- 
1705) and J. P. Tournefort (1656-1708) continued and 
advanced the work of Caesalpinus considerably. 

Q. 284. Who is the founder of Modern Botany ? 

A. Modern Botany as well as modern zoology ac- 
knowledges Carl von Linne or Linnaeus (1707-1778), 
professor at the University of Upsala in Sweden, as 
their founder. He is the author of a system of classi- 
fication of plants, based upon the reproductive organs, 
viz. stamens and pistils; he brought order into the 
confusion that reigned prior to him. To him is due 
the binomial system of naming plants and animals, 
which is now in universal use. 



84 HISTORICAL BOTANY. 

Q. 285. With what names of men is the History of 
Botany connected principally since Linn's time ? 

A. Linn's system was artificial, i. e,, it took no 
account whatever of the natural affinities of plants. 
A. L. de Jussieu (1748-1836) of Paris was the first to 
classify plants according to their natural affinities, 
whence his system is called the Natural system. His 
system was approved and improved by A. P. De Can- 
dolle (1778-1841), Robert Brown (1775-1858), and 
Endlicher (1804-1849). The next great advance in 
Botany is due to the establishment of the cell-theory 
by M. J. Schleiden (1804-1881) for Botany at the same 
time that it was established in Zoology by Theodore 
Schwan, Professor at Louvain (1838). Hugo von Mohl 
(1805-1872) was a successful worker in plant Anatomy 
and Physiology, and he is said to have given the 
living substance its present name protoplasm. 
Darwin (1809-1882), in his work, ^The Origin of 
Species,'' in which he advances the celebrated theory 
of evolution of plants and animals by ^'natural se- 
lection,'' gave a great impulse to the study of 
natural science especially by his untiring zeal in the 
collection and arrangement of facts and observations 
bearing on the distribution, development and 
behavior of plants. Brogniart (1801-1876) developed 
the science of Fossil Botany ; Alexander von Hum- 
boldt (1769-1859) rendered great service to plant- 
geography. 

Q. 286. Mention the principal botanists that have 
written about North American plants ? 
A. They are the following : Michaux (1746-1802), 



ORIGIN OF PLANTS. 85 

Pursh (1774-1820), Rafinesque (1784-1842) and Nut- 
tal (1786-1859), and especially, Asa Gray, Professor of 
Botany, at Harvard University, born 1810, died 1888"^ 
who was one of the leading botanists of his age. 



CHAPTER XXVI. 



ORIGIN OF PLANTS. 

Q. 287. What is the origin of plants, i. e., where 
did the first plants of each species come from ? 

There are two theories regarding the origin of 
plants, viz., (1) the theory of constancy or separate 
creation ; (2) the theory of evolution. 

Q. 288. What does the theory of constancy hold ? 

A. The theory of constancy holds that all the true 
species of plants that now exist or that existed in 
bygone geological ages, were each separately and dis- 
tinctly created by Omnipotent God, the Lord and 
ruler of the universe. 

Q. 289. What does the theory of evolution hold? 

A. In the first place, it is to be noted that there are 
quite a number of so-called theories of evolution 
which agree only on one point, namely, in opposition 
to the theory of constancy, so that whereas the latter 
theory denies the possibility of true new species to 
arise from preceding ones according to the laws of 
nature and without the direct intervention of the 
Creator, the former holds and affirms this same possi- 
bility to exist. 



86 ORIGIN OF PLANTS. 



Q. 290. What important distinction is there among 
the different theories of evolution ? 

A. The most important distinction between the 
theories of evolution rests upon the fact that one set of 
theories admits a personal Creator, and consequently 
the creation of matter, together with its properties and 
the laws of nature, as they are called ; while the 
other set of evolutionary theories holds the eternity 
of matter, its properties and the laws of nature, and 
consequently denies the existence of a personal 
Creator. The adherents of the former are called the 
christian or theistic school of evolutionists, while 
the adherents of the latter are known as the atheistic, 
monistic, materialistic or rationalistic school. 

Q. 291. Has any one of all these theories been 
proved to be true ? 

A. Neither the theory of constancy nor any of the 
theories of evolution has been demonstrated to be the 
true explanation of the origin of species, at least in 
detail ; but it is undoubtedly true that the great 
majority of men skilled in the natural sciences, 
especially biologists, do admit the fact of evolution, 
although there is still great diversity of opinion 
among them as regards the cause and manner of 
evolution, so that no particular theory can be said to 
be universally accepted. 

Q. 292. What are the most renowned theories of 
evolution ? 

A. They are the following : 1. Lamarck's theory 
of adaption (1809). 2. Chas. Darwin's, Herbert 
Spencer's, A. Wallace's, and Huxley's Theory of 



ORIGIN OF PLANTS. 87 

^•'Natural Selection^^ or ^^Survival of the Fittest/' (1859) 
and the latest, Hugo de Vries' Mutation theory (1901). 

Q. 293. On what facts is the theory of constancy 
based ? 

A. On the following : 1. On the observed con- 
stancy of species in historical times as far as trust- 
worthy records show. 2. On the infertility of hybrids, 
1 6., offspring of distinct species. 3. On the important 
fact, that no new species, truly and strictly so-called, 
has actually been observed to arise. 

Q. 294. On what facts are the theories of evolution 
based ? 

A. Following are some of the most important: 1. 
The variability of individuals within specific limits. 
2. The fact that the fossil species exhibit a gradation 
in perfection of organization and specialization, which, 
at least in a general way, is in accordance with the 
geological age of the strata in which the fossils are 
found. 3. The fact, that many species, and of these, 
some in a remarkable and unmistakable manner, 
exhibit adaptation to their surroundings. 4. The 
widespread occurrence of metamorphosis. 5. The 
occurrence of rudimentary organs. 

Q. 295. What are some of the principal facts opposed 
to the monistic theory of evolution ? 

They are the following : 1. The all but demon- 
strated impossibility of spontaneous generation. 2. 
The unmistakable evidences of purpose in nature as 
found especially in truly wonderful contrivances for 



ORIGIN OF PLANTS. 



cross fertilization in plants and equally in the instincts 
of animals. 3. The metaphysical contradiction, in- 
volved in the assertion of the eternity of matter and 
energy. 

Say, what impels, amid surrounding snow. 
Congealed, the Crocus' flamy bud to grow ? 
Say, what retards amid the summer's blaze. 
The autumnal flower, till pale declining days ? 
The God of Seasons, whose pervading power 
Controls the sun, and sheds the fleecy shower ; 
He bids each flower his quick'ning word obey. 
Or to teach lingering bloom enjoins delay. 



IN 



LOfC. 



APPENDIX. 89 



APPENDIX. 



ON THE FORMATION OP AN HERBARIUM, OR HORTUS 

SICCUS. 

The description and figure of plants, however 
amply and correctly they may be given in books, can 
be neither so instructive nor so satisfactory to the 
young student in Botany, as when he has the works 
of Nature before him, and can examine and investi- 
gate for himself, without the danger of being misled 
by the errors or misconceptions of others. It will be 
proper, therefore, to give a few directions, by which 
the plants that he has examined may be preserved, 
and formed into a collection for occasional reference. 

Several methods have been recommended for pre- 
serving plants, but the best appears to be that of 
drying them. Most plants dry with facility between 
the leaves of books or other paper ; and a collection 
of bound newspapers will be found well adapted to 
the purpose. If there be a sufficiency of paper, they 
often dry best without shifting ; but if the specimens 
be crowded, they must be taken out frequently, and 
the paper dried before they are replaced. Some 
vegetables are so tenacious of the vital principle, 
that they will grow between papers ; but that incli- 
nation must be prevented by immersion in boiling 
water or by the application of a hot iron, such as is 
used for linen, after which they are easily dried, 



90 APPENDIX. 



In spreading the plants bstween papers, too much 
nicety and precision should not be observed in arrang- 
ing their leaves and branches, in order to give them a 
picturesque appearance, as it takes away from their 
natural aspect ; except, however, for the purpose of 
displaying the internal parts of one or two of the 
flowers, for ready observation. When properly dried, 
the specimens are best preserved by being fastened 
with weak carpenter's glue to detached sheets of 
paper, or in a blank book, with the name, the time, 
and place of finding, or any other concise piece of 
information, written on the opposite leaf. When the 
book is full, an alphabetical index may be made to the 
page. The herbarium thus formed will be found to 
keep best in a dry room without a constant fire. 

Specimens should be gathered on a dry day, and 
carried home in a japanned tin box, in which they 
will keep for several days better than in water, should 
anything occur to prevent their immediate use. If 
the stem be woody, it may be thinned with a knife : 
and when the fiower is thick or globular, as the 
thistle, one side of it may be carefully cut away, it 
being only necessary in a specimen to preserve the 
character of the class, order, genus, and species. 

By this means the production of our own, or of the 
most distant countries, may be brought together 
under our eyes at any season of the year ; and, in the 
midst of winter, our minds may be regaled with a 
semblance of spring, while the still verdant speci- 
mens will recall to our recollection the many pleasant 
excursions undertaken to procure them. 



UG 22 1905 



i 




LIBRARY OF CONGRESS 



n nns 336 724 






